CN102277457A - Collagen-lossless circular dechroming method of chrome-containing leather waste in leather working by ethylenediaminetetraacetic acid under photocatalysis - Google Patents
Collagen-lossless circular dechroming method of chrome-containing leather waste in leather working by ethylenediaminetetraacetic acid under photocatalysis Download PDFInfo
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- CN102277457A CN102277457A CN201110168857A CN201110168857A CN102277457A CN 102277457 A CN102277457 A CN 102277457A CN 201110168857 A CN201110168857 A CN 201110168857A CN 201110168857 A CN201110168857 A CN 201110168857A CN 102277457 A CN102277457 A CN 102277457A
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02W—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO WASTEWATER TREATMENT OR WASTE MANAGEMENT
- Y02W30/00—Technologies for solid waste management
- Y02W30/50—Reuse, recycling or recovery technologies
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Abstract
The invention discloses a collagen-lossless circular dechroming method of chrome-containing leather waste in leather working by ethylenediaminetetraacetic acid (EDTA) under photocatalysis. The method is characterized by comprising the following steps: mixing 100 parts of chrome-containing leather waste, 20 to 50 parts of EDTA and 100 to 500 parts of water; regulating the pH value to be 3 to 8; repeatedly dechroming the chrome-containing leather waste at the temperature of between 30 and 60 DEG C; further removing residual trace chrome in ultraviolet photocatalysis under the same condition after massive chrome is removed; regulating the pH value of the filtrate prepared in the performed process to be less than 0.5 with sulfuric acid, heating at the temperature of between 40 and 80 DEG C for 5 to 12 hours, cooling to separate EDTA crystal, and circularly using the EDTA crystal as a dechroming agent; and repeatedly using chromium sulfate in a liquid phase as a chrome tanning agent in leather working. According to the method, the structure of collagen in the leather waste can be well maintained, the chrome removal rate is over 98 percent, the process operation is simple, and the dechroming agent and collagen removed chrome can be recycled.
Description
Technical field
The present invention is specifically related to the circulation dechromium method that a kind of process hides contains the harmless photochemical catalysis disodium ethylene diamine tetraacetate (EDTA) of chromium leather leftover collagen, belongs to the recovery of chrome leather scrap waste in the process hides and utilizes the field.
Background technology
Tanning industry can produce a large amount of chrome leather scrap solid waste inevitably, in this class solid waste, is collagen protein more than 80%, and 3%-5% is a chromium.Chromium and collagen mortise also form crosslinkedly at the collagen peptide interchain, make this class solid waste be difficult to be degraded by microorganisms, and trivalent chromium wherein might be oxidized to the supervirulent sexavalent chrome of tool, cause serious environmental to be polluted.Handling the useless admittedly key of this class is high efficiency separation chromium and collagen protein, and keeps the structure of collagen protein as much as possible, is beneficial to follow-up efficient utilization.
From bibliographical information and industry investigation situation analysis, the main technical schemes of research/enforcement at present comprises: acid system, alkaline process, enzyme process and oxidation style, and be basic deutero-combination treatment method with this several method, as the acid-alkali alternative method, alkali-enzyme alternative method etc.Acid system, alkaline process and enzyme process promptly adopt acid, alkali, enzymic hydrolysis collagen, make trivalent chromium water-soluble, by regulating pH, chromium are separated with collagen hydrolysate with the form of chromium hydroxide precipitation at last.And oxidation style promptly is under the weak base condition, uses strong oxidizer (H commonly used
2O
2) chromium in the chrome leather scrap is oxidized to sexavalence by trivalent, thus become dissolubility chromate and separate with collagen.From the result that these methods obtain, its major technique deficiency is: 1) acid, be difficult to effectively open the connection of chromium and collagen when alkali takes off chromium, chromium removes endless.Human acid such as Backoba are done and are taken off the chromium agent, and to take off the chromium rate only be 40% to vitriolic as a result, oxalic acid also only reach 70% (Wang Yuanliang, DECHROMIZATION OF WASTE CLASTIC CHROMING SKIN.Chinese leather, 19 (10), 4-7; 2) usage quantity of acid, alkali, enzyme and oxygenant is big slightly, and the hydrolysis aggravation of materials with hide glue fibril forms very high gelatin and the hydrolytic collagen of viscosity, not only be difficult to from system chromium be separated, and the utilize scope and the value of collagen also reduces greatly.As taking off chromium with alkaline process among the Chinese patent CN1041547SA, collagen destroys serious, can only obtain extracting solution of protein; 3) take off chromium agent acid, alkali, enzyme and oxygenant and can not recirculation use the serious secondary pollution of generation.As Chinese patent CN1481427A, introduced uniting of a kind of organic acid and organic acid salt and taken off the chromium method.This method is less to the structure deteriorate of collagen, repeatedly take off chromium and can reach 99.6% the chromium rate of taking off, but complicated operation takes off the chromium agent and is difficult to recycle; Chinese patent CN1464072A has introduced a kind of ultrasound oxidation technology and has taken off chromium, under the effect of 20kHz ultrasonic wave, repeatedly take off and take off the chromium rate behind the chromium and can reach 99%, but residual poisonous hexavalent chromium toxicity is big, is difficult to handle; Simultaneous oxidation agent H
2O
2Consumption is big, the expense height.
Summary of the invention
The present invention seeks to provide the recovery of the chrome leather scrap waste that the harmless height of a kind of collagen takes off the chromium rate and the circulation dechromium method of utilization at the deficiencies in the prior art, be characterized in forming a kind of take off chromium rate height, collagen destroy less, take off the method that the chromium agent can recycle.
Purpose of the present invention is realized by following technical measures, states that wherein the raw material umber is parts by weight except that specified otherwise.
Process hides contains the harmless photochemical catalysis EDTA circulation dechromium method of chromium leather leftover collagen and comprises the steps:
(1). pre-treatment
Chrome leather scrap is ground into 100 parts of 3-5mm fragments, adds suitable quantity of water and make it submergence, soaked 3-7 days;
(2). the chrome leather scrap that step (1) was handled washes with water 1-3 time for 100 parts, each 10-30min, suction filtration discharge opeing;
(3). disodium ethylene diamine tetraacetate 20-50 part is added in 100-500 part water, stir it is fully dissolved, add 100 parts of step (2) gained chrome leather scraps, regulate pH=3-8, in temperature 30-60 ℃, oscillatory reaction device discontinuous stirring reaction 1-3 days;
(4). 100 parts of the chrome leather scraps that step (3) was handled, wash 2-5 time at normal temperatures, each 10-30min adds suitable quantity of water then and soaks 1-3h, suction filtration discharge opeing;
(5). select to take off the chromium number of times according to the chrome content of chrome leather scrap, 100 parts of repeated multiple times of chrome leather scrap that step (3) was handled taken off chromium, again with chrome leather scrap set by step under (3) the same terms, under UV-irradiation intermittence stirring reaction 1-3 days;
(6). with 100 parts of washings of step (5) gained chrome leather scrap 1-3 time, in temperature 30-50 ℃ drying;
(7). with step (3) and (5) gained filtrate, add sulfuric acid regulation solution pH＜0.5, in temperature 40-80 ℃ of heating 5-12h, after the cooling, the disodium ethylene diamine tetraacetate crystal is separated out, and filters, washing adds the dissolving of concentration 5-10wt% sodium hydroxide solution, reuses as taking off the chromium agent; Chromium sulphate in the liquid phase is reused as the chrome tanning agent in the process hides.
Performance test:
Adopt sulfuric acid-nitric acid will take off chromium bits before and after the chromium and carry out measuring total chrome content in the solution with atom absorption method after wet method clears up, calculate the chromium rate of taking off.Adopt the method mensuration of sulfuric acid disassociation recrystallization to take off the chromium agent EDTA rate of recovery; Detailed being shown in Table 1.The result shows that it is 98.7% that the present invention takes off the chromium rate.The rate of recovery of taking off the chromium agent is 80%.
The present invention has the following advantages compared with prior art:
1. technological operation is simple, and it is higher to take off the chromium rate;
2. do not have the use of strong acid, alkali and oxygenant in taking off the chromium process, collagen structure destructive degree is very little, and molecular weight is bigger, helps taking off the follow-up high-value-use of leather bits collagen behind the chromium;
3. take off and reclaim cycling and reutilization after chromium agent EDTA can add the sulfuric acid crystallization, generate chromium sulphate simultaneously and can be used for process hides tanning process once more, the pollution once more of powerlessness waste and environment, this invention has not only reduced cost, but also meets the requirement of the useless green chemical industry process of handling admittedly.
Embodiment
Below by embodiment the present invention is carried out concrete description; be necessary to be pointed out that at this present embodiment only is used for the present invention is further specified; can not be interpreted as limiting the scope of the invention, the person skilled in the art in this field can content according to the present invention make some nonessential improvement and adjustment.
Embodiment 1
Process hides contains the harmless photochemical catalysis EDTA circulation dechromium method of chromium leather leftover collagen and comprises the steps:
1. pre-treatment: chrome leather scrap is ground into 100 parts of 3mm fragments, adds suitable quantity of water and make it submergence, soaked 4 days;
2. the chrome leather scrap of step 1 being handled washes with water 2 times for 100 parts, each time 20min, suction filtration discharge opeing;
3. 30 parts of EDTA are added in 300 parts of water, stir it is fully dissolved, add 100 parts of step 2 gained chrome leather scraps, regulate pH=4, under 45 ℃ of temperature in 2 days oscillatory reaction device discontinuous stirring reaction time;
4. the chrome leather scrap of step 3 being handled is washed 3 times for 100 parts at normal temperatures, each time 20min, after add suitable quantity of water soak time 1h, the suction filtration discharge opeing;
5. 100 parts of the chrome leather scraps that will handle 35 times repeatedly set by step set by step under 3 the same terms, 2 days following reaction times of UV-irradiation, intermittently stir 2 times repeatedly with chrome leather scrap then;
6 with 100 parts of washings of step 5 gained chrome leather scrap 1 time, in 30 ℃ of dryings of temperature;
7. with step 3 and 5 gained filtrates, add sulfuric acid regulation solution pH＜0.5, in 40 ℃ of heating of temperature 12h, after the cooling, the disodium ethylene diamine tetraacetate crystal is separated out, and filters, and washing adds the dissolving of concentration 5-10wt% sodium hydroxide solution, reuses as taking off the chromium agent; Chromium sulphate in the liquid phase is reused as the chrome tanning agent in the process hides.
Embodiment 2
Process hides contains the harmless photochemical catalysis EDTA circulation dechromium method of chromium leather leftover collagen and comprises the steps:
1. pre-treatment: chrome leather scrap is ground into 100 parts of 5mm fragments, adds suitable quantity of water and make it submergence, soaked 5 days;
2. the chrome leather scrap of step 1 being handled washes with water 2 times for 100 parts, each time 20min, suction filtration discharge opeing;
3. 40 parts of EDTA are added in 250 parts of water, stir it is fully dissolved, add 100 parts of step 2 gained chrome leather scraps, regulate pH=5, under 45 ℃ of temperature in the oscillatory reaction device 2 days reaction times, intermittently stir;
4. the chrome leather scrap of step 3 being handled is washed 3 times for 100 parts at normal temperatures, each time 20min, after add suitable quantity of water soak time 1h, the suction filtration discharge opeing;
5. 100 parts of the chrome leather scraps that will handle 35 times repeatedly set by step set by step under 3 the same terms, 2 days following reaction times of UV-irradiation, intermittently stir 2 times repeatedly with chrome leather scrap then;
6 with 100 parts of washings of step 5 gained chrome leather scrap 2 times, in 40 ℃ of dryings of temperature;
7. with step 3 and 5 gained filtrates, add sulfuric acid regulation solution pH＜0.5, in 50 ℃ of heating of temperature 7h, after the cooling, the disodium ethylene diamine tetraacetate crystal is separated out, and filters, and washing adds the dissolving of concentration 5-10wt% sodium hydroxide solution, reuses as taking off the chromium agent; Chromium sulphate in the liquid phase is reused as the chrome tanning agent in the process hides.
Embodiment 3
Process hides contains the harmless photochemical catalysis EDTA circulation dechromium method of chromium leather leftover collagen and comprises the steps:
1. pre-treatment: chrome leather scrap is ground into 100 parts of 4mm fragments, adds suitable quantity of water and make it submergence, soaked 5 days;
2. the chrome leather scrap of step 1 being handled washes with water 2 times for 100 parts, each time 20min, suction filtration discharge opeing;
3. 35 parts of EDTA are added in 250 parts of water, stir it is fully dissolved, add 100 parts of step 2 gained chrome leather scraps, regulate pH=5, under 55 ℃ of temperature in the oscillatory reaction device 2 days reaction times, intermittently stir;
4. the chrome leather scrap of step 3 being handled is washed 3 times for 100 parts at normal temperatures, each time 20min, after add suitable quantity of water soak time 1h, the suction filtration discharge opeing;
5. 100 parts of the chrome leather scraps that will handle 34 times repeatedly set by step set by step under 3 the same terms, 1 day following reaction times of UV-irradiation, intermittently stir 3 times repeatedly with chrome leather scrap then;
6 with 100 parts of washings of step 5 gained chrome leather scrap 3 times, in 40 ℃ of dryings of temperature;
7. with step 3 and 5 gained filtrates, add sulfuric acid regulation solution pH＜0.5, in 60 ℃ of heating of temperature 8h, after the cooling, the disodium ethylene diamine tetraacetate crystal is separated out, and filters, and washing adds the dissolving of concentration 5-10wt% sodium hydroxide solution, reuses as taking off the chromium agent; Chromium sulphate in the liquid phase is reused as the chrome tanning agent in the process hides.
Embodiment 4
Process hides contains the harmless photochemical catalysis EDTA circulation dechromium method of chromium leather leftover collagen and comprises the steps:
1. pre-treatment: chrome leather scrap is ground into 100 parts of 5mm fragments, adds suitable quantity of water and make it submergence, soaked 5 days;
2. the chrome leather scrap of step 1 being handled washes with water 2 times for 100 parts, each time 20min, suction filtration discharge opeing;
3. 35 parts of EDTA are added in 250 parts of water, stir it is fully dissolved, add 100 parts of step 2 gained chrome leather scraps, regulate pH=6, under 50 ℃ of temperature in the oscillatory reaction device 2 days reaction times, intermittently stir;
4. the chrome leather scrap of step 3 being handled is washed 3 times for 100 parts at normal temperatures, each time 20min, after add suitable quantity of water soak time 1h, the suction filtration discharge opeing;
5. with step 34 times repeatedly, select to take off the chromium number of times according to the chrome content of chrome leather scrap, then with chrome leather scrap set by step 3 the same terms intermittently stirred 2 times repeatedly in 2 days following reaction times of UV-irradiation;
6 with 100 parts of washings of step 5 gained chrome leather scrap 3 times, in 50 ℃ of dryings of temperature;
7. with step 3 and 5 gained filtrates, add sulfuric acid regulation solution pH＜0.5, in 70 ℃ of heating of temperature 7h, after the cooling, the disodium ethylene diamine tetraacetate crystal is separated out, and filters, and washing adds the dissolving of concentration 5-10wt% sodium hydroxide solution, reuses as taking off the chromium agent; Chromium sulphate in the liquid phase is reused as the chrome tanning agent in the process hides.
Embodiment 5
Process hides contains the harmless photochemical catalysis EDTA circulation dechromium method of chromium leather leftover collagen and comprises the steps:
1. pre-treatment: chrome leather scrap is ground into 100 parts of 3mm fragments, adds suitable quantity of water and make it submergence, soaked 5 days;
2. the chrome leather scrap of step 1 being handled washes with water 2 times for 100 parts, each time 20min, suction filtration discharge opeing;
3. 40 parts of EDTA are added in 200 parts of water, stir it is fully dissolved, add 100 parts of step 2 gained chrome leather scraps, regulate pH=6, under 55 ℃ of temperature in the oscillatory reaction device 2 days reaction times, intermittently stir;
4. the chrome leather scrap of step 3 being handled is washed 3 times for 100 parts at normal temperatures, each time 20min, after add suitable quantity of water soak time 1h, the suction filtration discharge opeing;
5. 100 parts of the chrome leather scraps that will handle 35 times repeatedly set by step set by step under 3 the same terms, 2 days following reaction times of UV-irradiation, intermittently stir 2 times repeatedly with chrome leather scrap then;
6 with 100 parts of washings of step 5 gained chrome leather scrap 2 times, in 50 ℃ of dryings of temperature;
7. with step 3 and 5 gained filtrates, add sulfuric acid regulation solution pH＜0.5, in 80 ℃ of heating of temperature 5h, after the cooling, the disodium ethylene diamine tetraacetate crystal is separated out, and filters, and washing adds the dissolving of concentration 5-10wt% sodium hydroxide solution, reuses as taking off the chromium agent; Chromium sulphate in the liquid phase is reused as the chrome tanning agent in the process hides.
Embodiment 6
Process hides contains the harmless photochemical catalysis EDTA circulation dechromium method of chromium leather leftover collagen and comprises the steps:
1. pre-treatment: chrome leather scrap is ground into 100 parts of 4mm fragments, adds suitable quantity of water and make it submergence, soaked 5 days;
2. the chrome leather scrap of step 1 being handled washes with water 2 times for 100 parts, each time 20min, suction filtration discharge opeing;
3. 30 parts of EDTA are added in 300 parts of water, stir it is fully dissolved, add 100 parts of step 2 gained chrome leather scraps, regulate pH=7, under 50 ℃ of temperature in the oscillatory reaction device 2 days reaction times, intermittently stir;
4. the chrome leather scrap of step 3 being handled is washed 3 times for 100 parts at normal temperatures, each time 20min, after add suitable quantity of water soak time 1h, the suction filtration discharge opeing;
5. 100 parts of the chrome leather scraps that will handle 35 times repeatedly set by step set by step under 3 the same terms, 2 days following reaction times of UV-irradiation, intermittently stir 2 times repeatedly with chrome leather scrap then;
6 with 100 parts of washings of step 5 gained chrome leather scrap 3 times, in 30 ℃ of dryings of temperature;
7. with step 3 and 5 gained filtrates, add sulfuric acid regulation solution pH＜0.5, in 60 ℃ of heating of temperature 10h, after the cooling, the disodium ethylene diamine tetraacetate crystal is separated out, and filters, and washing adds the dissolving of concentration 5-10wt% sodium hydroxide solution, reuses as taking off the chromium agent; Chromium sulphate in the liquid phase is reused as the chrome tanning agent in the process hides.
Table 1
Claims (1)
1. a process hides contains the harmless photochemical catalysis disodium ethylene diamine tetraacetate circulation dechromium method of chromium leather leftover collagen, it is characterized in that this method comprises the steps, is by weight:
(1). pre-treatment
Chrome leather scrap is ground into 100 parts of 3-5mm fragments, adds suitable quantity of water and make it submergence, soaked 3-7 days;
(2). the chrome leather scrap that step (1) was handled washes with water 1-3 time for 100 parts, each 10-30min, suction filtration discharge opeing;
(3). disodium ethylene diamine tetraacetate 20-50 part is added in 100-500 part water, stir it is fully dissolved, add 100 parts of step (2) gained chrome leather scraps, regulate pH=3-8, in temperature 30-60 ℃, oscillatory reaction device discontinuous stirring reaction 1-3 days;
(4). 100 parts of the chrome leather scraps that step (3) was handled, wash 2-5 time at normal temperatures, each 10-30min adds suitable quantity of water then and soaks 1-3h, suction filtration discharge opeing;
(5). select to take off the chromium number of times according to the chrome content of chrome leather scrap, 100 parts of repeated multiple times of chrome leather scrap that step (3) was handled taken off chromium, again with chrome leather scrap set by step under (3) the same terms, under UV-irradiation intermittence stirring reaction 1-3 days;
(6). with step (5) gained chrome leather scrap washing 1-3 time, in temperature 30-50 ℃ drying;
(7). with step (3) and (5) gained filtrate, add sulfuric acid regulation solution pH＜0.5, in temperature 40-80 ℃ of heating 5-12h, after the cooling, the disodium ethylene diamine tetraacetate crystal is separated out, and filters, washing adds the dissolving of concentration 5-10wt% sodium hydroxide solution, reuses as taking off the chromium agent; Chromium sulphate in the liquid phase is reused as the chrome tanning agent in the process hides.
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|---|---|---|---|
| CN2011101688570A CN102277457B (en) | 2011-06-22 | 2011-06-22 | Collagen-lossless circular dechroming method of chrome-containing leather waste in leather working by ethylenediaminetetraacetic acid under photocatalysis |
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| CN2011101688570A CN102277457B (en) | 2011-06-22 | 2011-06-22 | Collagen-lossless circular dechroming method of chrome-containing leather waste in leather working by ethylenediaminetetraacetic acid under photocatalysis |
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| CN102277457A true CN102277457A (en) | 2011-12-14 |
| CN102277457B CN102277457B (en) | 2013-09-11 |
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| CN2011101688570A Expired - Fee Related CN102277457B (en) | 2011-06-22 | 2011-06-22 | Collagen-lossless circular dechroming method of chrome-containing leather waste in leather working by ethylenediaminetetraacetic acid under photocatalysis |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN111077094A (en) * | 2020-01-15 | 2020-04-28 | 南大盐城环境检测科技有限公司 | Method for detecting hexavalent chromium in soil |
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| RU2182930C1 (en) * | 2001-07-02 | 2002-05-27 | Общество с ограниченной ответственностью "Курская кожа" | Leather waste dechromation process |
| CN1888075A (en) * | 2005-06-28 | 2007-01-03 | 广东海洋大学 | Process of extracting collagen from fish scale |
| CN101109022A (en) * | 2007-08-16 | 2008-01-23 | 山东轻工业学院 | Leather wet blue and method of doffing chromium in normal temperature and at original position from its leftovers |
| CN101260141A (en) * | 2008-04-29 | 2008-09-10 | 四川大学 | Method for preparing protein filling material for leather preparation by using leather preparation chromium-containing leftover material as raw material |
| CN101525674A (en) * | 2009-04-02 | 2009-09-09 | 西藏自治区拉萨皮革厂 | Method for stabilizing content of trivalent chromium and minimum hexavalent chromium in leather |
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2011
- 2011-06-22 CN CN2011101688570A patent/CN102277457B/en not_active Expired - Fee Related
Patent Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| RU2182930C1 (en) * | 2001-07-02 | 2002-05-27 | Общество с ограниченной ответственностью "Курская кожа" | Leather waste dechromation process |
| CN1888075A (en) * | 2005-06-28 | 2007-01-03 | 广东海洋大学 | Process of extracting collagen from fish scale |
| CN101109022A (en) * | 2007-08-16 | 2008-01-23 | 山东轻工业学院 | Leather wet blue and method of doffing chromium in normal temperature and at original position from its leftovers |
| CN101260141A (en) * | 2008-04-29 | 2008-09-10 | 四川大学 | Method for preparing protein filling material for leather preparation by using leather preparation chromium-containing leftover material as raw material |
| CN101525674A (en) * | 2009-04-02 | 2009-09-09 | 西藏自治区拉萨皮革厂 | Method for stabilizing content of trivalent chromium and minimum hexavalent chromium in leather |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
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| CN111077094A (en) * | 2020-01-15 | 2020-04-28 | 南大盐城环境检测科技有限公司 | Method for detecting hexavalent chromium in soil |
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