CN109647327A - A kind of preparation method and applications carrying lanthanum modified attapulgite - Google Patents
A kind of preparation method and applications carrying lanthanum modified attapulgite Download PDFInfo
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- CN109647327A CN109647327A CN201811067061.4A CN201811067061A CN109647327A CN 109647327 A CN109647327 A CN 109647327A CN 201811067061 A CN201811067061 A CN 201811067061A CN 109647327 A CN109647327 A CN 109647327A
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- B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
- B01J20/00—Solid sorbent compositions or filter aid compositions; Sorbents for chromatography; Processes for preparing, regenerating or reactivating thereof
- B01J20/02—Solid sorbent compositions or filter aid compositions; Sorbents for chromatography; Processes for preparing, regenerating or reactivating thereof comprising inorganic material
- B01J20/0203—Solid sorbent compositions or filter aid compositions; Sorbents for chromatography; Processes for preparing, regenerating or reactivating thereof comprising inorganic material comprising compounds of metals not provided for in B01J20/04
- B01J20/0207—Compounds of Sc, Y or Lanthanides
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
- B01J20/00—Solid sorbent compositions or filter aid compositions; Sorbents for chromatography; Processes for preparing, regenerating or reactivating thereof
- B01J20/02—Solid sorbent compositions or filter aid compositions; Sorbents for chromatography; Processes for preparing, regenerating or reactivating thereof comprising inorganic material
- B01J20/10—Solid sorbent compositions or filter aid compositions; Sorbents for chromatography; Processes for preparing, regenerating or reactivating thereof comprising inorganic material comprising silica or silicate
- B01J20/12—Naturally occurring clays or bleaching earth
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- C—CHEMISTRY; METALLURGY
- C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F1/00—Treatment of water, waste water, or sewage
- C02F1/28—Treatment of water, waste water, or sewage by sorption
- C02F1/281—Treatment of water, waste water, or sewage by sorption using inorganic sorbents
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- C—CHEMISTRY; METALLURGY
- C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F2101/00—Nature of the contaminant
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Abstract
The invention discloses a kind of preparation methods for carrying lanthanum modified attapulgite, comprising the following steps: after mixing attapulgite in proportion with acid or hydrochlorate, appropriate amount of deionized water S1, is added, after stirring at normal temperature 30min, it is centrifuged, it is dry, grinding, sieves with 100 mesh sieve, obtains attapulgite powder；S2, after resulting attapulgite powder and certain density lanthanum solution are mixed in the ratio of solid-to-liquid ratio 1: 10, constant temperature oscillation for 24 hours, filters, 105 DEG C of dry 2h at 25 DEG C, grinds, sieves with 100 mesh sieve, it is attapulgite modified must to carry lanthanum；S3, it roasts resulting load lanthanum is attapulgite modified, grinds, sieving is attapulgite modified to get lanthanum is carried.Compared with former attapulgite, the resulting load modified attapulgite of lanthanum of the present invention significantly improves the adsorption effect of As (III), and it is easier to be separated from water than attapulgite after carrying the modified attapulgite absorption heavy metal of lanthanum, can preferably apply in water process.
Description
Technical field
The present invention relates to environmental pollution control technique fields, and in particular to it is a kind of carry lanthanum modified attapulgite preparation method and
It is applied.
Background technique
Arsenic (Arsenic, As) is widely present in water, air, soil and the rock of nature, is a kind of toxic eka-gold
Belong to.Inorganic arsenic gross morphology in water body has trivalent (AsO2 -) or pentavalent (AsO4 3-).The toxicity of trivalent arsenic is the 60 of pentavalent arsenic
Times, in human body, pentavalent arsenic can be reduced into trivalent.Maximum contamination level Arsenic in Drinking Water is suggested by the World Health Organization (WHO)
Content must not be higher than 10 μ g/L.Currently, arsenic pollution is had found in the surface water of many countries and regions, so one kind is selected to go
Except the small method for removing arsenic in water removal of high-efficient, secondary pollution is particularly important.Commonly go arsenic removal method have ion-exchange,
Biochemical method, the precipitation method, electrolysis method, absorption method.Absorption method is due to easy to operate, removal effect is preferable by favor.Adsorbent
Selection determines the cost that arsenic removal is gone with absorption method, so finding inexpensive efficient adsorbent becomes hot research topic.
Common adsorbent has zeolite, active carbon, biology and biomass etc., however mentioned kind adsorbent is due to adsorbance
It is relatively low, expensive, be easy to produce the reasons such as secondary pollution, can not be widely applied.Attapulgite (ATP) is that one kind is rich in
The silicate mineral of magnesium, aluminium, as adsorbent due to large specific surface area, cheap and easy to get, but natural attapulgite's surface band is negative
Electricity is unfavorable for its absorption to anion in water, so needing to be modified it to improve absorption property.Pan Min etc. is to bumps
Stick soil carries out heat modification, the results showed that, 9.66mg/g can reach to the absorption of phosphate radical when 700 DEG C, pH are 6；Shi Wanli etc.
Attapulgite is modified with the hydrochloric acid of 1mol/L, the results showed that, attapulgite to the adsorption efficiency of copper ion more before modified
Promote 38.61%；Wang Ying etc. is attapulgite modified with polydimethyl diallyl ammonium chloride, the results showed that, modified bumps
The adsorption capacity of stick soil Pyrogentisinic Acid enhances, and when pH=6~8, phenol concentration are 10mg/L, removal rate is inhaled up to 89%
It is attached renewable.
The oxide of rare-earth elements of lanthanum has had been demonstrated higher Anion-adsorption ability, and the absorption that can be applied to water body is net
Change research.But directly the oxide of lanthanum is added in polluted-water and removes anion, it is not easily recycled, furthermore lanthanum element oxygen
Compound is expensive, is added directly and will increase processing cost, and the oxide of lanthanum is easy to accumulate in water body, increases mass transfer resistance
Power limits adsorption capacity.
Summary of the invention
To solve the above problems, the present invention provides a kind of preparation method that load lanthanum is attapulgite modified, the load lanthanum is modified
Attapulgite is easier with preferable adsorption effect, and after its absorption heavy metal than attapulgite to arsenic in waste water and moisture
From can preferably apply in water process.
To achieve the above object, the technical scheme adopted by the invention is as follows:
A kind of preparation method carrying lanthanum modified attapulgite, which comprises the following steps:
S1, it after mixing attapulgite in proportion with acid or hydrochlorate, is added in the ratio that solid-to-liquid ratio is 1: 5~1: 10 appropriate
Deionized water after stirring at normal temperature 30min, is centrifuged, dry, and grinding sieves with 100 mesh sieve, obtains attapulgite powder；
S2, after resulting attapulgite powder and certain density lanthanum solution are mixed in the ratio of solid-to-liquid ratio 1: 10,25
Constant temperature oscillation for 24 hours, filters, 105 DEG C of dry 2h at DEG C, and grinding sieves with 100 mesh sieve, it is attapulgite modified must to carry lanthanum；
S3, it roasts resulting load lanthanum is attapulgite modified, grinds, sieving is attapulgite modified to get lanthanum is carried.
Further, the mass ratio of attapulgite and acid or hydrochlorate is 100: 3 in the step S1.
Further, the acid or hydrochlorate are one of hydrochloric acid, sodium pyrophosphate etc..
Further, the lanthanum solution is one of lanthanum chloride, lanthanum hydroxide, lanthanum nitrate etc..
Further, the concentration of the lanthanum chloride is 0.55~0.65mol/L.
Further, maturing temperature is 100 DEG C~300 DEG C, and the time is 2~4h.
Further, the attapulgite modified partial size of lanthanum that carries is less than 100 mesh.
Further, it after the mixture for completing stirring being centrifuged 2min under 3000r/min revolving speed in the step S1, is placed in
105 DEG C of dry 2h in thermostatic drying chamber.
The present invention is resulting to carry the attapulgite modified application of lanthanum, which is characterized in that it can be used for removing the arsenic in waste water.
The mass concentration of the arsenic in waste water is not higher than 1mg/L, and the attapulgite modified ratio that adds of lanthanum that carries is 6~7g/L.
The invention has the following advantages:
(1) compared with former attapulgite, the resulting modified attapulgite of lanthanum that carries of the present invention imitates the absorption of As (III)
Fruit significantly improves, and is easier to be separated from water than attapulgite after carrying the modified attapulgite absorption heavy metal of lanthanum, can
Preferably apply in water process.
(2) by optimization experiment, the concentration for obtaining lanthanum chloride when modified is 0.61mol/L, pH value is 6.8 and adsorbent
Dosage be 0.38g when carry the attapulgite modified removal rate to As in water (III) of lanthanum reach 99% or more.
Detailed description of the invention
Fig. 1 is to carry the attapulgite modified influence to As (III) absorption of lanthanum.
Influence of Fig. 2 chlorination la concn to arsenic adsorption effect.
Fig. 3 carries the attapulgite modified optimum dosage of lanthanum.
Influence of Fig. 4 pH to adsorption effect.
Influence of Fig. 5 adsorption time to lanthanum attapulgite absorption As (III) effect is carried.
Fig. 6 carries lanthanum attapulgite to As (III) adsorption process dynamics pseudo-first-order (a), quasi- second level (b) and intra-particle diffusion
(c) models fitting.
Fig. 7 carry lanthanum attapulgite to As in water (III) Tellurium determination Langmuir (a), Freundlich (b) and
Temkin (c) models fitting.
Van ' the t-Hoof equation linear regression result of Fig. 8 adsorption thermodynamic parameters.
Fig. 9 attapulgite and load lanthanum attapulgite infrared absorpting light spectra.
Figure 10 attapulgite (a, b) and the SEM comparison diagram before and after lanthanum attapulgite (c, d) arsenic-adsorbing.
Specific embodiment
The present invention is described in detail combined with specific embodiments below.Following embodiment will be helpful to the technology of this field
Personnel further understand the present invention, but the invention is not limited in any way.It should be pointed out that the ordinary skill of this field
For personnel, without departing from the inventive concept of the premise, various modifications and improvements can be made.These belong to the present invention
Protection scope.
Embodiment
The pretreatment of attapulgite: in order to remove the impurity in attapulgite crystal channel.With attapulgite and pyrophosphoric acid
Sodium mass ratio is to add the deionized water of 800ml, blender stirring at normal temperature 30min, in centrifuge in 100: 3 addition beakers
In to be centrifuged 2min under 3000r/min revolving speed, be put into 105 DEG C of dry 2h in thermostatic drying chamber later, grind, sieve with 100 mesh sieve, it is standby
With.
Carry the preparation of lanthanum attapulgite: it is pre- that prepared a certain concentration lanthanum chloride solution by solid-to-liquid ratio 1: 10 is added to 5g
In treated attapulgite, gained mixed liquor constant temperature oscillation at 25 DEG C for 24 hours, is filtered, 105 DEG C of dry 2h, grinding, mistake 100
Mesh, it is spare.
Experimental method
Carry the modified influence to adsorption effect of lanthanum
The pretreated concave convex rod of 0.1g, 0.2g, 0.3g, 0.4g, 0.5g, 0.6g is added into polytetrafluoroethylene (PTFE) bottle respectively
Native (ATP) and the modified attapulgite of lanthanum (La-ATP) is carried, adds As (III) solution that 50ml mass concentration is 1mg/L,
It is placed in 25 DEG C of constant-temperature tables with the velocity fluctuation of 200r/min for 24 hours, takes out supernatant, cross 0.45 μm of filter membrane, it is to be measured.Lanthanum chloride
Influence of the concentration to adsorption effect
Prepare 0mol/L, 0.1mol/L, 0.2mol/L, 0.3mol/L, 0.4mol/L, 0.5mol/L, 0.6mol/L,
The lanthanum chloride solution of 0.8mol/L, 1mol/L prepare the modified load lanthanum attapulgite of different chlorination la concns.
Each 0.2g of load lanthanum attapulgite for taking various concentration modified is each that 50ml mass is added in polytetrafluoroethylplastic plastic bottle
Concentration is As (III) solution of 1mg/L, is placed in 25 DEG C of constant-temperature tables with the velocity fluctuation of 200r/min for 24 hours, takes out supernatant
Liquid crosses 0.45 μm of filter membrane, to be measured.
Influence of the adsorbent dosage to adsorption effect
Take modified load lanthanum attapulgite 0.1g, 0.2g, 0.3g, 0.4g, 0.5g, 0.6g, 0.8g, 1g, 2g in order
It is added in polytetrafluoroethylplastic plastic bottle, it is each that As (III) solution that 50ml mass concentration is 1mg/L is added, it is placed in 25 DEG C of constant temperature and shakes
In bed for 24 hours with the velocity fluctuation of 200r/min, supernatant is taken out, 0.45 μm of filter membrane is crossed, it is to be measured.
Influence of the different pH to adsorption effect
Take polytetrafluoroethylplastic plastic bottle is several to be divided into two groups, its pH value is adjusted to 2 respectively with NaOH and HCl, 3,4,5,6,
7,8,9,10, the pretreated attapulgite 0.3g of one group of addition, another group of addition carries lanthanum attapulgite 0.3g, is placed in 25 DEG C of perseverances
In warm shaking table for 24 hours with the velocity fluctuation of 200r/min, supernatant is taken out, 0.45 μm of filter membrane is crossed, it is to be measured.
Optimal adsorption condition is probed into based on response surface
To carry the attapulgite modified maximum material removal rate to arsenic of lanthanum as optimizing index, according to the basis of experiment of single factor early period
On, it is tested using the BBD of three factor levels respectively to the dosage X of adsorbent1, carry lanthanum it is modified when lanthanum chloride concentration X2, solution
PH value X3As three factors of experiment, and each factor selects three levels, is examined and is selected using Design Expert
It is simulated to be desirably to obtain to be fitted experimental data with polynary quadratic regression and carries the attapulgite modified optimal conditions to arsenic absorption of lanthanum.
Orthogonal experiment factor level is shown in Table 1.
1 design factor of table coding and level
The adsorption kinetic data
0.3g is added in polytetrafluoroethylplastic plastic bottle and carries lanthanum attapulgite, adding 50ml mass concentration is 1mg/L's
As (III) solution is placed in 25 DEG C of constant-temperature tables 200r/min and vibrates, respectively at 5,20,40,120,240,480,720,960,
1200,1440min is sampled, and takes out supernatant, crosses 0.45 μm of filter membrane, to be measured.
Isothermal thermodynamics adsorption experiment
Prepare initial concentration 0.1,0.2,0.5,1,2,4,6,8,10mgL-1As (III) solution, take 9 polytetrafluoroethyl-nes
It is separately added into 0.3g in alkene bottle and carries lanthanum attapulgite, sequentially adds prepared various concentration As (III) solution 50mL, is placed in
200r/min oscillation for 24 hours, takes out supernatant in the constant-temperature table that temperature is 25 DEG C, crosses 0.45 μm of filter membrane, to be measured.Analysis and test
Method
Sample to be tested measures concentration adsorbance, the removal rate of arsenic in solution with atomic fluorescence spectrophotometer after treatment
Calculation formula is as follows:
In formula, QeAdsorbance (μ gg when being adsorption equilibrium-1)；C0It is initial concentration (the μ gL of arsenic solution-1)；Ce is
When adsorption equilibrium in solution arsenic concentration (μ gL-1)；M is adsorbent mass (g)；V is arsenic solution volume；η is the removal of arsenic
Rate.
Characterizing method
FTIR analysis: chemical structure point is carried out to lanthanum modified attapulgite soil material is carried using Fourier Transform Infrared Spectrometer
Analysis, material is uniformly mixed with the potassium bromide of chromatographically pure, is pressed into tablet press machine general with infrared spectroscopy light after the thin slice of homogeneous transparent
Instrument scans and draws FTIR spectrum figure.
Sigma scanning electron microscope analysis: utilizing electronics beam scanning sample surfaces, by secondary electron, backscattered electron
Acquisition, obtains the information of substance microscopic appearance；By attapulgite and the attapulgite modified sample preparation respectively of lanthanum is carried, is then utilized
The transmitting of Sigma 500 scanning electron microscope scans under different multiples obtains picture concerned.
Experimental result and analysis
Carry the modified influence to adsorption effect of lanthanum
Fig. 1 is attapulgite (ATP) and carries lanthanum attapulgite modified (La-ATP) to pair of As in water (III) removal effect
Than.It can be seen from the figure that the removal rate of As (III) and the dosage of two kinds of materials are positively correlated increase in water.Attapulgite
Carry the modified removal rate to As (III) of lanthanum improve 30%~35%, this may be because lanthanum element mainly by with calcium,
Iron plasma occurs ion exchange and successfully loads to attapulgite's surface[14], and rare-earth elements of lanthanum has preferably anion
Suction-operated, it is therefore, significantly raised to the removal rate of As in water (III).
Influence of the chlorination la concn to adsorption effect
Fig. 2 is the experimental result that chlorination la concn influences As (III) adsorption effect, it can be seen from the figure that in chlorination
When la concn is within the scope of 0~0.6mol/L, modified attapulgite is positively correlated to As (III) adsorption effect, works as lanthanum chloride
When concentration is 0.6mol/L, the attapulgite modified removal rate to As (III) reaches 98.96%, but when chlorination la concn is super
When crossing 0.6mol/L, the attapulgite modified removal rate to As (III) is begun to decline, this may be because of each activity of attapulgite
Site is occupied by lanthanum ion, and attapulgite loaded lanthanum ion reaches saturation state, and remaining lanthanum ion blocks inside attapulgite
Duct[26], therefore its adsorption ability reduces, so the optium concentration for carrying selective chlorination lanthanum when lanthanum is modified is 0.6mol/L.
Influence of the adsorbent dosage to adsorption effect
Fig. 3 is the experimental result for carrying the attapulgite modified optimum dosage of lanthanum, it can be seen from the figure that with adsorbent
The increase of dosage, it is bigger to the removal rate of As in water (III), but the adsorbance of adsorbent is to reduce.The throwing of adsorbent
When dosage is 0.3g, 96% has been reached to the removal rate of As in water (III), when the dosage of adsorbent is greater than 0.3g, removal
The effect that rate increases is unobvious, but adsorbance dramatic reduction, so selecting optimum dosage of the 0.3g as adsorbent.
Influence of the different pH to adsorption effect
Fig. 4 is the experimental result that pH influences adsorption effect, it can be seen from the figure that solution ph is to unmodified concave convex rod
Soil and the load attapulgite modified adsorption effect to As (III) of lanthanum have larger impact, when pH value is 6, unmodified concave convex rod
Soil and the load attapulgite modified adsorption effect to As (III) of lanthanum reach best, and unmodified attapulgite and load lanthanum are modified concave-convex
Stick soil is respectively 58.62% and 98.2% to the removal rate of As (III).It is, with the increase of pH, not change in 2~6 ranges in pH
Property attapulgite and carry that lanthanum is attapulgite modified all enhances As in water (III) adsorption effect.It is attapulgite modified for carrying lanthanum,
It may be that the lanthanum ion of adsorption is desorbed because changing the surface characteristic of adsorbent under acid condition[16], acidity gets over
By force, lanthanum ion desorption is more, causes to reduce As (III) adsorption effect.For unmodified attapulgite, it may be possible to because
Under acid condition, H+The pore structure for destroying attapulgite changes existing crystal structure, makes Ca2+、Mg2+Loss causes pair
As (III) adsorption effect reduces.It is in 6~8 ranges in pH, with the increase of pH, unmodified attapulgite and load lanthanum modification are recessed
Convex stick soil all weakens As in water (III) adsorption effect, this is because under alkaline condition higher concentration OH-Meeting and arsenous anion
Hydrolyze the adsorption site on the anion competitive adsorption agent surface generated[17], hinder the absorption to As (III).It is 8~10 in pH
In range, unmodified attapulgite slightly enhances the adsorption effect of As (III), and it is attapulgite modified to As's (III) to carry lanthanum
Adsorption effect first weakens and enhances afterwards, so the optimal pH for selecting reaction is 6.
Optimal adsorption condition is probed into based on response surface
Each factor and its level value are sequentially input into system, then generates testing program table, is shown in Table 2, is carried out according to the program
Test, records the test result of every group of factor combination, and test result is inserted respective column.
The design of 2 response surface experiments of table and result
Construct model and inspection
Test result is analyzed using Design-Expert software, first clicks on Analysis button, to linear letter
It counting, 2FI model, second-order model, third-order model carry out significance test, and by being detected to the detection of model conspicuousness, the quasi- item of mistake,
The data of correlation test compare, and recommend suitable model.This testing program result recommends to use second-order model.Then
(clicking ANOVA button) carries out variance analysis and significance test according to the model of selection.It can be to influence two in variance analysis
The constant term of equation of n th order n model, first order, quadratic term (interaction item), quadratic term (curved surface effect) conspicuousness examined
It tests, as shown in table 3.
The analysis of variance table of 3 regression equation of table
Note: SS- variation quadratic sum, DF- freedom degree, MS- is square, the probability simulation regression equation that Pr > F- does not make significant difference
Are as follows: η=97.24+9.56X1+0.022X2+2.24X3+3.25X1X2+5.31X1X3-2.68X2X3-13.14X1 2-6.64X2 2-
7.37X3 2
Big F value and small P value represent the conspicuousness of related coefficient.It is regarded by the Pr > F value < 0. of analysis of variance model
It is that significantly, the good response surface approximate model that can use of fitting precision carries out subsequent optimization experiment for model.It can by table 3
To find out, which is that significantly, can carry out subsequent optimization experiment.
The analysis of 4 regression equation error statistics of table
Adj R-Squared and Pred R-Squared (RAdj2-RPred2 < 0.2) the two values are high and close, then return
Return model that can absolutely prove technical process；Not high then explanation is insufficient to Interpretations, and it is significant need to consider whether that there are other
Impact factor.As can be seen from Table 4, which can absolutely prove technical process.CV < 10% illustrates the credible of experiment
Degree and accuracy are high, and precision (Adeq Precision) is the ratio of useful signal and noise, and it is reasonable for being greater than 4.From table 4
As can be seen that the precision of the experiment meets the requirements.
Response phase method, which also overcomes orthogonal experiment, cannot provide the defect of visual picture, be done respectively according to quadratic equation model
Interactive 3 D stereo response surface and contour map between empirical factor out, investigate that in some factor to be fixed on central value constant
In the case where, influence of the reciprocation of other two factors to As (III) removal rate can intuitively be found out, dosage and
Modified concentration, dosage and pH value significant interaction；Modified concentration and pH value reciprocation be not significant.The removal of As (III)
Rate has maximum value under suitable dosage and modified concentration conditions, which appears in the dosage for carrying lanthanum attapulgite
In (0.3~0.4g) range, concentration is modified as in (0.55~0.65mol/L) range.The removal rate of As (III) is suitably being thrown
Under dosage and pH value condition, have maximum value, the value appear in carry lanthanum attapulgite dosage (0.3~0.35g) range in,
In pH value (5.5~6.3) range.The removal rate of As (III) has maximum value, and when pH value is 6, the change of modified concentration is to As
(III) removal rate influences less, and illustrating that the maximum value of the removal rate of As (III) appears in pH value is near 6, because of the two interaction
Effect is not significant, and modified concentration should be maintained in (0.55~0.65mol/L) range.
Adsorption dynamics adsorption kinetics research
This experiment is 1mg/L, water-bath oscillation carrying the attapulgite modified dosage 0.3g of lanthanum, the initial solubility of arsenic solution
The revolving speed of device carries out adsorption experiment under conditions of being 200r/min.Respectively at 5min, 20min, 40min, 120min, 240min,
It is sampled when 480min, 720min, 960min, 1200min, 1440min, measures adsorbance corresponding with the time.It is inhaled using arsenic
Attached amount formula draws adsorbance QtIt obtains carrying the attapulgite modified absorption dynamic curve of lanthanum with the relationship of t.
It is increased rapidly within 2h from fig. 5, it can be seen that carrying the attapulgite modified adsorbance to arsenic of lanthanum, it is basic in 8h
Reach equilibrium state, is finally 112 μ g/g to the adsorbance of As (III), this is because effective absorption point of adsorbent surface
As the increase in reaction time is fewer and fewer, the absorption of arsenic is gradually tended to be saturated.
Pseudo-first-order kinetics equation linear representation:
lg(qe-qt)=lgqe-k1t (3)
Pseudo-second order kinetic equation linear representation:
Kannan modified intra-particle diffusion model expression formula:
qt=kidt1/2+Ci
In formula, qeAnd qtWhen respectively representing adsorption equilibrium and the adsorbance of t moment, μ g/g；k1、k2And kidOne subject to respectively
Grade, quasi- second level, intra-particle diffusion coefficient, wherein kidThe diffusive transport mechanism of molecule in description absorption and parsing；T is the time,
min。
The rate constant and q of 5 pseudo-first-order kinetics equation of table, pseudo-second order kinetic equation and modified intra-particle diffusion modele
Calculated value and experiment value compare
Pseudo-first-order kinetic model basic assumption is that adsorbate occupies the rate of adsorption site and the number of sites not being occupied
Mesh is directly proportional.The model is often not suitable for the entire adsorption process of description, but this meets the description to physical adsorption process.Quasi- second level
The basic assumption of kinetic model is that the adsorption process of adsorbate on the sorbent is mainly chemisorption.It can from table 5
Out, the R of pseudo-second order kinetic equation model2It is 0.9993, it is higher than pseudo-first-order kinetics equation degree of fitting, and calculated value more connects
Nearly experiment value shows that pseudo-second order kinetic equation can preferably describe to carry the attapulgite modified absorption power to As (III) of lanthanum
Process.Illustrate that the adsorption process is physical absorption and the process that chemisorption combines.
Carry the attapulgite modified isothermal thermodynamic study to As (III) absorption of lanthanum
Tellurium determination is for describing the equilibrium relation between adsorbent and adsorbate, affinity and the absorption of adsorbent
Capacity also has important reference value in terms of annotating thermodynamic parameter, determining between adsorbent and adsorbate.
This experiment is in the dosage 0.3g for carrying lanthanum attapulgite, and the initial concentration of arsenic solution is 1mg/L, and temperature is respectively 35 DEG C, 45 DEG C
It is tested under conditions of with 55 DEG C, and experimental result is fitted with three kinds of thermodynamical models.
The isotherm adsorption model of Langmuir, Freundlich and Temkin equation classics, the research is by experimental data
It is fitted with these three equations, to describe physical absorption and chemisorption, to help to illustrate that load lanthanum is attapulgite modified to As
(III) mechanism adsorbed.
Langmuir equation belongs to theory deduction formula:
l/qe=kd/(qm·ce)+l/qm (5)
It assumes that absorption is that solute and solvent are two-dimensional ideal solution, solute and solvent in mono layer adsorption and adsorption layer
The volume of molecule is approximately equal or has identical adsorption potential；Regard the absorption of solute as in body phase solution solute molecule and absorption
The result for the solvent molecule exchange being adsorbed in layer.
Freundlich is index adsorption isotherm, belongs to pure empirical equation:
Fruendlich Adsorption Model is an experience different based on out-phase adsorption or surface site affinity
Formula, it is assumed that stronger binding site is first occupied, and as site coverage rate increases, bond strength is reduced[20].Temkin equation
The linear reduction of heat of adsorption in adsorption process between molecule[21]:
Q=A+Blgce (7)
In formula, qeFor equilibrium adsorption capacity, μ g/g；ceTo balance mass concentration, μ g/L；qmFor maximal absorptive capacity, μ g/g；kd、
kf, n, A, B be constant.
6 thermodynamics fitting parameter of table
As can be seen from Table 6, Freundlich equation and Langmuir equation linear dependence reach the level of signifiance.And
The fitting effect of Freundlich equation is substantially better than the fitting effect of Langmuir equation.Illustrate Freundlich adsorption isotherm
Model more properly describes to carry the attapulgite modified absorption to As in water (III) of lanthanum.By Freundlich adsorption isotherm model
Physical significance may determine that, carry in the attapulgite modified adsorption process to As in water (III) of lanthanum, stronger binding site elder generation quilt
In conjunction with the increase of site coverage rate, binding force is constantly reduced.When its parameter n > 1, adsorption process is preferential absorption.Table 6
Middle Freundlich equation parameter n shows to carry the attapulgite modified process to As (III) absorption of lanthanum between 1.03~1.23
For preferential absorption[22].Langmuir equation assumes that adsorbate is adsorbed in adsorbent surface homogeneous monomolecular layer, and finally absorption is steady
It is fixed, it can estimate maximum adsorption capacity Qm, according to equation RL=1/ (1+KL·C0), wherein C0For initial concentration solution (μ g/L), if
Its value then shows that the adsorption process is preferential absorption between 0~1[23].It is 308.15~328.15K range in vibration temperature
It is interior, can be calculated carry lanthanum it is attapulgite modified to As (III) absorption during RLValue shows to carry lanthanum between 0.37~0.72
The attapulgite modified process to As (III) absorption is preferential absorption.The conclusion of this and the n value theory in Freundlich equation
It is consistent.
The analysis of 2.8 Adsorption thermodynamics
According to adsorption isotherm experiment as a result, thermodynamic parameter gibbs free energy change, enthalpy change and Entropy Changes can be by formula (8) and formulas
(9) it obtains
Δ G=-RTlnKL (8)
Δ G=Δ H-T Δ S (9)
In formula, R is universal gas constant, 8.314J/ (molK)；K is temperature, K；KL=qe/Ce, it is solid phase and liquid phase
Between distribution coefficient mL/g, formula (10) can be obtained in joint type (8) and formula (9)
The thermodynamic parameter of 7 adsorption process of table
According to formula (8) and formula (9), calculated Δ H, Δ S and Δ G the results are shown in Table 7.As seen from table, under different temperatures
Δ G is respectively less than zero, illustrate carry the attapulgite modified adsorption process to As (III) of lanthanum be it is spontaneous, Δ H is positive value, explanation
The reaction is the endothermic reaction.Δ S is positive value, shows that the process is the increased behavior of entropy.
Sample characterization
FTIR spectrum (FTIR) analysis
Functional group possessed by adsorbent material itself and modified is determined by carrying out FTIR analysis to adsorbent material
The functional group for losing or generating provides theoretical foundation to probe into adsorption mechanism.FTIR after attapulgite carries lanthanum before modified divides
It is as shown in Figure 9 to analyse result.
For unmodified attapulgite, in 980cm-1、1045cm-1、1195.4cm-1、1658.8cm-1And 3553.5cm-1There is diffraction peak, 980cm in place-1The peak at place represents Si-O vibration, 1195.4cm-1The peak at place represents (Mg, Al)-O vibration,
1658.8cm-1The peak at place represents intermediary water adsorption peak, 3553.5cm-1The peak at place represents R-OH key chattering[24].It is modified to carry lanthanum
Attapulgite, in 676cm-1There is diffraction peak in place, which indicates La-OH vibration[25], show that lanthanum successfully loads to concave convex rod
Above native.In 1195.4m-1Locate peak value to weaken, sufficiently demonstrating and carrying the mode of lanthanum is by containing in lanthanum ion and attapulgite
Mg, Al occur ion exchange.In 3553.5cm-1The peak value at place obviously weakens, and shows to carry the modified structure for making attapulgite of lanthanum
Changed.
Scanning electron microscope (SEM) analysis
It carries the attapulgite modified SEM figure of lanthanum and sees Figure 10, attapulgite is have layer structure and hole configurations aqueous
Rich magnesium silicate clay schemes a for original attapulgite SEM figure, and as can be seen from the figure its structure is stratiform and hole really, is had
Biggish specific surface area, this is also one of the reason of attapulgite can be used as adsorbent.Scheming c is to carry lanthanum treated concave convex rod
Soil, it can be seen from the figure that carrying the modified attapulgite of lanthanum is attached with strip colloid particle, this may be exactly in load
The roughness of lanthanum ion, the surface of attapulgite increases.Figure b and figure d is respectively attapulgite and the load attapulgite modified suction of lanthanum
Picture after attached As (III) illustrates really as can be seen that adsorbent surface has adsorbed white colloidal class particle really from picture
It is real to have suction-operated to As (III).
Specific embodiments of the present invention are described above.It is to be appreciated that the invention is not limited to above-mentioned
Particular implementation, those skilled in the art can make a variety of changes or modify within the scope of the claims, this not shadow
Ring substantive content of the invention.In the absence of conflict, the feature in embodiments herein and embodiment can any phase
Mutually combination.
Claims (10)
1. a kind of preparation method for carrying lanthanum modified attapulgite, which comprises the following steps:
S1, by attapulgite and acid or after hydrochlorate mix in proportion, the ratio addition for being 1: 5~1: 10 by solid-to-liquid ratio is appropriate go from
Sub- water after stirring at normal temperature 30min, is centrifuged, dry, and grinding sieves with 100 mesh sieve, obtains attapulgite powder；
S2, after resulting attapulgite powder and certain density lanthanum solution are mixed in the ratio of solid-to-liquid ratio 1: 10, at 25 DEG C
Constant temperature oscillation for 24 hours, filters, 105 DEG C of dry 2h, and grinding sieves with 100 mesh sieve, it is attapulgite modified must to carry lanthanum；
S3, it roasts resulting load lanthanum is attapulgite modified, grinds, sieving is attapulgite modified to get lanthanum is carried.
2. a kind of preparation method for carrying lanthanum modified attapulgite as described in claim 1, which is characterized in that the step S1 concave
The mass ratio of convex stick soil and acid or hydrochlorate is 100: 3.
3. a kind of preparation method for carrying lanthanum modified attapulgite as described in claim 1, which is characterized in that the acid or hydrochlorate are
One of hydrochloric acid, sodium pyrophosphate.
4. a kind of preparation method for carrying lanthanum modified attapulgite as described in claim 1, which is characterized in that the lanthanum solution is chlorine
Change one of lanthanum, lanthanum hydroxide, lanthanum nitrate.
5. a kind of preparation method for carrying lanthanum modified attapulgite as claimed in claim 4, which is characterized in that the lanthanum chloride it is dense
Degree is 0.55~0.65mol/L.
6. a kind of preparation method for carrying lanthanum modified attapulgite as described in claim 1, which is characterized in that maturing temperature 100
DEG C~300 DEG C, the time is 2~4h.
7. a kind of preparation method for carrying lanthanum modified attapulgite as described in claim 1, which is characterized in that the load lanthanum modification is recessed
The partial size of convex stick soil is less than 100 mesh.
8. a kind of preparation method for carrying lanthanum modified attapulgite as described in claim 1, which is characterized in that will in the step S1
After the mixture for completing to stir is centrifuged 2min under 3000r/min revolving speed, it is placed in 105 DEG C of dry 2h in thermostatic drying chamber.
9. carrying the attapulgite modified application of lanthanum as claim 1-8 is described in any item, which is characterized in that it can be used for removing
Arsenic in waste water.
10. application as claimed in claim 9, which is characterized in that the mass concentration of the arsenic in waste water is not higher than 1mg/L, institute
Stating and carrying the attapulgite modified ratio that adds of lanthanum is 6~7g/L.
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Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
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| CN110592766A (en) * | 2019-09-19 | 2019-12-20 | 界首市远航织带有限公司 | Preparation method of nylon woven tape with high dye-uptake |
| CN110721656A (en) * | 2019-10-29 | 2020-01-24 | 江苏开放大学（江苏城市职业学院） | Method for optimizing Pb (II) adsorption condition of modified attapulgite by BP-PSO (Back propagation-PSO) and application |
| CN111569850A (en) * | 2020-05-11 | 2020-08-25 | 河海大学 | Attapulgite loaded zirconia adsorbent and preparation and detection methods thereof |
| CN113941333A (en) * | 2021-10-25 | 2022-01-18 | 四川轻化工大学 | Preparation method and application of bimetal-loaded attapulgite catalyst |
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2018
- 2018-09-04 CN CN201811067061.4A patent/CN109647327A/en not_active Withdrawn
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN110592766A (en) * | 2019-09-19 | 2019-12-20 | 界首市远航织带有限公司 | Preparation method of nylon woven tape with high dye-uptake |
| CN110721656A (en) * | 2019-10-29 | 2020-01-24 | 江苏开放大学（江苏城市职业学院） | Method for optimizing Pb (II) adsorption condition of modified attapulgite by BP-PSO (Back propagation-PSO) and application |
| CN111569850A (en) * | 2020-05-11 | 2020-08-25 | 河海大学 | Attapulgite loaded zirconia adsorbent and preparation and detection methods thereof |
| CN111569850B (en) * | 2020-05-11 | 2022-12-09 | 河海大学 | Attapulgite loaded zirconia adsorbent and preparation and detection methods thereof |
| CN113941333A (en) * | 2021-10-25 | 2022-01-18 | 四川轻化工大学 | Preparation method and application of bimetal-loaded attapulgite catalyst |
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