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Ferrihydrite-ultra-filtration (UF) membrane combination process for removing trivalent arsenic and disinfection by-product precursors

A combined process and trivalent arsenic technology, applied in the field of water treatment, can solve the problems of large pore size of UF membrane, limit the popularization and application of UF membrane, and it is difficult to effectively remove inorganic ions and DBPs precursors, etc., and achieve the effect of reducing the transmembrane pressure difference

Inactive Publication Date: 2018-09-07
BEIJING NORMAL UNIVERSITY +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, the large pore size of the UF membrane makes it difficult to effectively remove inorganic ions and DBPs precursors
In addition, DOM will cause membrane fouling, which limits the popularization and application of UF membranes.

Method used

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  • Ferrihydrite-ultra-filtration (UF) membrane combination process for removing trivalent arsenic and disinfection by-product precursors

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0021] In the membrane reaction system, polyvinylidene fluoride UF membrane was used alone without adding adsorbent to remove trivalent arsenic and DOM. Add trivalent arsenic concentration 0.1mg / L and DOM concentration 5.0mg / L to the aqueous solution, at 150L / (m 2 · h) under the condition of constant current operation. DOC removal rate 31.2%, UV 254 The removal rate is 40.1%, the removal rate of THMs precursor is 30.5%, the removal rate of HAAs precursor is 38.6%, and it has no removal effect on trivalent arsenic.

Embodiment 2

[0023] In the membrane reaction system, trivalent arsenic and DOM were removed synergistically by adsorbent FH and polyvinylidene fluoride UF membrane. Add FH concentration 50mg / L-Fe, trivalent arsenic concentration in the feed solution is 0.1mg / L, DOM concentration is 5.0mg / L, at 150L / (m 2 · h) under the condition of constant flow, the transmembrane pressure does not change much during the operation. DOC removal rate 80.3%, UV 254 The removal rate is 91.4%, the removal rate of trivalent arsenic is 99.4%, and the concentration of trivalent arsenic in the effluent is lower than 0.01mg / L, meeting the drinking water standard.

Embodiment 3

[0025] Wipe off the DOM and adsorbent particles accumulated on the surface of the FH-UF membrane after filtration, and then backwash. Macromolecular DOM is the main pollutant that causes UF membrane fouling, and FH has a strong adsorption capacity for macromolecular DOM. After FH was added, a large amount of DOM was adsorbed, and a loose filter cake layer was formed on the membrane surface, which reduced the transmembrane pressure difference by 76.2%.

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Abstract

The invention relates to a ferrihydrite (FH)-ultra-filtration (UF) membrane combination process for removing trivalent arsenic and dissolved organic matters (DOMs) in water, so as to control disinfection by-products (DBPs) and relieve membrane pollution, belonging to the technical field of water treatment. The process comprises the following steps: adding an adsorbent FH into a hollow fiber UF membrane filtration system, maintaining a suspension state by means of aeration, providing a shearing force to reduce the enrichment of pollutants on the surface of the membrane, and separating out the adsorbent from the water by means of UF membrane filtration. The process utilizes the trivalent arsenic to bond with monoatomic or diatomic O on the surface of FH, and simultaneously enables the FH andthe DOMs to be subjected to a coordination exchange reaction so as to form a coordination complex, so that 99.4% of the trivalent arsenic, 80.2% of a trihalomethane precursor and 90.4% of a haloacetic acid precursor are effectively removed, the concentrations of the arsenic and all the DBPs in effluent reach the drinking water standard, and the safety of drinking water is accordingly guaranteed.Furthermore, FH adsorption pretreatment reduces the enrichment of the DOMs on the surface of the membrane and the absorption inside membrane pores, so that the transmembrane pressure difference is reduced by 65.5%, and membrane fouling is significantly alleviated.

Description

technical field [0001] The invention relates to the technical field of water treatment, in particular to an adsorption-membrane combination process for removing trivalent arsenic and dissolved organic matter (DOM) in water, and controlling disinfection by-products (DBPs) and membrane pollution. Background technique [0002] Chlorine disinfection has been used by drinking water plants for more than 100 years as a cost-effective method of disinfecting drinking water. However, it is accompanied by the chemical reaction between the disinfectant and the organic pollutants and bromine or iodide in the water body while disinfecting and sterilizing, thus producing a series of DBPs. Hydrophobic acids (including humic acid and fulvic acid) are the main precursors of DBPs, and protein compounds can produce a large number of brominated DBPs. Among them, trihalomethanes (THMs) and haloacetic acids (HAAs) are the most important two types of DBPs produced during chlorine disinfection, whi...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C02F1/28C02F1/44C02F101/36C02F101/34C02F101/20
CPCC02F1/281C02F1/444C02F2101/20C02F2101/34C02F2101/36
Inventor 杨禹张森侯立安
Owner BEIJING NORMAL UNIVERSITY
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