WO2008154766A2 - Method of producing and recycling arsenic adsorbing materials from laterite - Google Patents

Method of producing and recycling arsenic adsorbing materials from laterite Download PDF

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Publication number
WO2008154766A2
WO2008154766A2 PCT/CH2008/000278 CH2008000278W WO2008154766A2 WO 2008154766 A2 WO2008154766 A2 WO 2008154766A2 CH 2008000278 W CH2008000278 W CH 2008000278W WO 2008154766 A2 WO2008154766 A2 WO 2008154766A2
Authority
WO
WIPO (PCT)
Prior art keywords
laterite
grains
arsenic
recycling
arsenate
Prior art date
Application number
PCT/CH2008/000278
Other languages
French (fr)
Other versions
WO2008154766A8 (en
WO2008154766A3 (en
Inventor
Con Hong Tran
Original Assignee
Bibus Ag
Hcth Tecnology Inc.
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Bibus Ag, Hcth Tecnology Inc. filed Critical Bibus Ag
Publication of WO2008154766A2 publication Critical patent/WO2008154766A2/en
Publication of WO2008154766A3 publication Critical patent/WO2008154766A3/en
Publication of WO2008154766A8 publication Critical patent/WO2008154766A8/en

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Classifications

    • 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
    • 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
    • B01J20/30—Processes for preparing, regenerating, or reactivating
    • B01J20/3021—Milling, crushing or grinding
    • 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
    • B01J20/30—Processes for preparing, regenerating, or reactivating
    • B01J20/3071—Washing or leaching
    • 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
    • B01J20/30—Processes for preparing, regenerating, or reactivating
    • B01J20/3078—Thermal treatment, e.g. calcining or pyrolizing
    • 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
    • B01J20/30—Processes for preparing, regenerating, or reactivating
    • B01J20/3085—Chemical treatments not covered by groups B01J20/3007 - B01J20/3078
    • 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
    • B01J20/30—Processes for preparing, regenerating, or reactivating
    • B01J20/34—Regenerating or reactivating
    • B01J20/3433—Regenerating or reactivating of sorbents or filter aids other than those covered by B01J20/3408 - B01J20/3425
    • 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
    • B01J20/30—Processes for preparing, regenerating, or reactivating
    • B01J20/34—Regenerating or reactivating
    • B01J20/345—Regenerating or reactivating using a particular desorbing compound or mixture
    • B01J20/3475—Regenerating or reactivating using a particular desorbing compound or mixture in the liquid phase
    • 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
    • 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
    • B01J2220/00—Aspects relating to sorbent materials
    • B01J2220/50—Aspects relating to the use of sorbent or filter aid materials
    • B01J2220/58—Use in a single column
    • 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
    • C02F2101/10—Inorganic compounds
    • C02F2101/103—Arsenic compounds

Definitions

  • the invention refers to a method of denaturating laterite by calcination and activation of the denaturated laterite surface to make it an adsorbant in order to eliminate arsenic from drinking water.
  • Bangladesh use clay which is heated to become terracotta (brick), ground and mixed with sand to filter arsenic containing water to make it drinking water.
  • This treatment method is not very effective, because after heating the adsorbability of the clay is reduced significantly and it is not safe to discharge used materials.
  • the purpose of the invention is to create a kind of material from natural laterite which has high arsenic adsorption capacity and can be recycled and does not pollute the environment.
  • the invention uses laterite with a high iron content instead of clay.
  • the material surface is activated to enable the material to have high adsorption capacity for arsenic.
  • the method includes the following steps: exploiting, calcinating for denaturation of laterite, grinding, classifying grains, activating the surface.
  • the activated laterite after saturation by arsenic adsorption will be washed, recycled and arsenic is collected as calcium arsenate.
  • the laterite used should normally have an iron content of 25-35%, with the rest being clay and other components. Laterite, after exploitation is naturally dried and then calcinated at the temperature of 900 to 950°C for 4 hours. Then it is cooled, ground and classified according to grain size and activated.
  • the activation process is performed as follows:
  • Step 1 Laterite grains are soaked in 1.0 N acid within 30 minutes; then the soaking solution is discharged.
  • Step 2 The material grains are continuously soaked in basic solution of 0.5 M NaOH within 30 minutes and then the solution is discharged.
  • Step 3 Using deionized water to wash out alkali and soluble ions and to obtain a neutral pH.
  • hydrochloric acid is used and the iron (III) concentration is controlled to an optimal range before neutralization by the NaOH solution. This will give the best effects.
  • the laterite grain material after activation and drying will be used to load into columns like water filtering columns.
  • the filtering columns can eliminate arsenic from drinking water to below 0.01 mg/1.
  • the laterite grain material after fully adsorbing arsenic will be recycled by washing with 0.2 M NaOH solution.
  • the arsenic in the washing solution will be precipitated by Ca(OH) 2 .
  • Insoluble calcium arsenate is collected and the NaOH washing solution is recovered.
  • the laterite grains are soaked in 20 1 of 0.5 M NaOH solution for 30 minutes, then all the NaOH solution is discharged and the laterite grains are washed with clean water without arsenic until a neutral reaction is measured. The grains are dried and 24.85 kg of the activated laterite grain material is collected. This is used for treating water in order to remove arsenic and obtain drinking water.
  • the method of this invention can adsorb arsenic stronger than heat - A -
  • denatured clay 1 kg of heat denatured clay adsorbs about 0.65 g arsenic whereas 1 kg of activated laterite grains can adsorb more than 6.00 g arsenic per kg of the material at the maximum. Furthermore, activated laterite can be recycled which reproduces activated surfaces to collect arsenate many times, whereas heat denatured clay cannot be recycled.

Abstract

The invention proposes a method of producing a laterite based adsorption material for removing arsenic from drinking water. The laterite is heated for denaturation and than surface - activated to improve the adsorption capacity of the material. The adsorption material can be recycled many times in a recycling method and arsenic is collected in the form of calcium arsenate salt. The method of production of the laterite based adsorption material includes the following steps: calcinating laterite for denaturating at a temperature of 900 - 950°C, grinding and sizing the grains, soaking the grains in acid, neutralizing by NaOH, washing out soluble ions, drying and collecting the surface-activated laterite grains as arsenic adsorption material.

Description

METHOD OF PRODUCING AND RECYCLING ARSENIC ADSORBING MATERIALS FROM LATERITE
FIELD OF THE INVENTION
The invention refers to a method of denaturating laterite by calcination and activation of the denaturated laterite surface to make it an adsorbant in order to eliminate arsenic from drinking water.
BACKGROUND OF THE INVENTION
It is known that the Bangladesh use clay which is heated to become terracotta (brick), ground and mixed with sand to filter arsenic containing water to make it drinking water. This treatment method is not very effective, because after heating the adsorbability of the clay is reduced significantly and it is not safe to discharge used materials.
In Vietnam up to now there have been no similar technologies announced and used in reality. DESCRIFΠON OF THE INVENTION
The purpose of the invention is to create a kind of material from natural laterite which has high arsenic adsorption capacity and can be recycled and does not pollute the environment. To reach the mentioned purpose, the invention uses laterite with a high iron content instead of clay. After calcinating for denaturation, the material surface is activated to enable the material to have high adsorption capacity for arsenic. The method includes the following steps: exploiting, calcinating for denaturation of laterite, grinding, classifying grains, activating the surface. The activated laterite after saturation by arsenic adsorption will be washed, recycled and arsenic is collected as calcium arsenate.
To perform the invention, the laterite used should normally have an iron content of 25-35%, with the rest being clay and other components. Laterite, after exploitation is naturally dried and then calcinated at the temperature of 900 to 950°C for 4 hours. Then it is cooled, ground and classified according to grain size and activated.
The activation process is performed as follows:
Step 1 : Laterite grains are soaked in 1.0 N acid within 30 minutes; then the soaking solution is discharged.
Step 2: The material grains are continuously soaked in basic solution of 0.5 M NaOH within 30 minutes and then the solution is discharged.
Step 3. Using deionized water to wash out alkali and soluble ions and to obtain a neutral pH.
According to a preferred embodiment of the invention, hydrochloric acid is used and the iron (III) concentration is controlled to an optimal range before neutralization by the NaOH solution. This will give the best effects. The laterite grain material after activation and drying will be used to load into columns like water filtering columns. The filtering columns can eliminate arsenic from drinking water to below 0.01 mg/1.
The laterite grain material after fully adsorbing arsenic will be recycled by washing with 0.2 M NaOH solution. The arsenic in the washing solution will be precipitated by Ca(OH)2. Insoluble calcium arsenate is collected and the NaOH washing solution is recovered.
EXAMPLE OF AN IMPLEMENTATION OF THE INVENTION
68.5 kg of laterite exploited in Thach That (Ha Tay), after naturally drying it yields 50 kg of dry laterite. Such 50 kg of dry laterite is calcinated in electric ovens for 4 hours at a temperature of 950 ± 10 °C. Then it is naturally cooled for 24 hours and ground by hammer grinding machines which have screens with 4 mm holes. Grains below 1 mm in size are eliminated and dust is washed out and a yield of 27.5 kg denatured laterite grains sized from 1 to 4 mm is collected. 25 kg of denatured laterite grains are soaked in 20 liters of 1.0 M HCl. After 30 minutes, the iron concentration is checked. When it reaches the optimal value, the acid solution is discharged. Next the laterite grains are soaked in 20 1 of 0.5 M NaOH solution for 30 minutes, then all the NaOH solution is discharged and the laterite grains are washed with clean water without arsenic until a neutral reaction is measured. The grains are dried and 24.85 kg of the activated laterite grain material is collected. This is used for treating water in order to remove arsenic and obtain drinking water.
EFFECTS OF THE METHOD ACCORDING TO THE INVENTION
By replacing clay with laterite and activation of the laterite surface after thermal denaturation, the method of this invention can adsorb arsenic stronger than heat - A -
denatured clay: 1 kg of heat denatured clay adsorbs about 0.65 g arsenic whereas 1 kg of activated laterite grains can adsorb more than 6.00 g arsenic per kg of the material at the maximum. Furthermore, activated laterite can be recycled which reproduces activated surfaces to collect arsenate many times, whereas heat denatured clay cannot be recycled.

Claims

P A T E N T C L A I M S
1. A method of producing arsenic adsorption material based on laterite for water treatment comprising the following steps: a) exploiting laterite, drying it , calcinating it for denaturation, and grinding it to yield grains b) soaking the grains in an acidic solution to activate the grain surface c) neutralizing the soaked grains, washing them for removing salts and drying them.
2. The method according to claim 1, wherein in step b) a concentration of iron (HI) ions in the acidic solution is controlled in order to optimize the binding capacity of the laterite grains.
3. The method according to claim 2, wherein the soaking time in the acidic solution is adjusted such that a predetermined iron (III) concentration is reached.
4. The method according to anyone of claims 1 - 3, wherein the calcination of step a) is at a temperature of 900 - 950°C and lasts for 4 hours.
5. The method according to anyone of claims 1 - 4, wherein the acidic solution used in step b) is HCl and the neutralizing in step c) is performed with NaOH.
6. A method for recycling laterite-based arsenic adsorption material for water treatment comprising a washing step with a basic washing solution in order to release the adsorbed arsenate from the laterite grains into the basic washing solution.
7. The recycling method according to claim 6, which further comprises a step treating the basic washing solution for precipitating the released arsenate in form of an insoluble arsenate salt.
8. The recycling method according to claim 6 or 7, wherein the basic washing solution comprises NaOH.
9. The recycling method according claims 7 or 8, wherein Ca(0H)2 is used for precipitating the arsenate.
PCT/CH2008/000278 2007-06-20 2008-06-20 Method of producing and recycling arsenic adsorbing materials from laterite WO2008154766A2 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
VN1-2007-01230 2007-06-20
VN200701230 2007-06-20

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WO2008154766A2 true WO2008154766A2 (en) 2008-12-24
WO2008154766A3 WO2008154766A3 (en) 2009-04-09
WO2008154766A8 WO2008154766A8 (en) 2010-03-18

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Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE102009035763A1 (en) * 2009-08-03 2011-02-10 Siemens Aktiengesellschaft Process and device for the removal of pollutants from drinking, industrial and industrial waters
CN110918096A (en) * 2019-12-17 2020-03-27 南京神克隆科技有限公司 Heterogeneous Fenton catalyst, application and wastewater treatment method

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US20030183579A1 (en) * 2002-03-29 2003-10-02 Sibdas Bandyopadhya Process for the preparation of arsenic free water, apparatus therefor, method for the manufacture of porous ceramics for use in pressure filtration to produce arsenic free water
JP2003334541A (en) * 2002-03-14 2003-11-25 Junjiro Kawasaki Method for removing arsenic, method for producing drinking water, and apparatus for removing arsenic

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JP2003334541A (en) * 2002-03-14 2003-11-25 Junjiro Kawasaki Method for removing arsenic, method for producing drinking water, and apparatus for removing arsenic
US20030183579A1 (en) * 2002-03-29 2003-10-02 Sibdas Bandyopadhya Process for the preparation of arsenic free water, apparatus therefor, method for the manufacture of porous ceramics for use in pressure filtration to produce arsenic free water

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Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE102009035763A1 (en) * 2009-08-03 2011-02-10 Siemens Aktiengesellschaft Process and device for the removal of pollutants from drinking, industrial and industrial waters
CN110918096A (en) * 2019-12-17 2020-03-27 南京神克隆科技有限公司 Heterogeneous Fenton catalyst, application and wastewater treatment method
CN110918096B (en) * 2019-12-17 2022-12-27 南京神克隆科技有限公司 Heterogeneous Fenton catalyst, application and wastewater treatment method

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WO2008154766A3 (en) 2009-04-09

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