Preparation Of Magnetically Core-shell Arsenic Adsorbent And Its Performance Of Arsenic Removal

Natural disasters and human activities will lead to arsenic release and pollution,and arsenic poisoning incidents occur from time to time.To avoid arsenic harm,researchers have done a lot of researches to remove arsenic from water.At present,adsorption method is one of the better options for arsenic removal,however the adsorption capacity and separation and regeneration performance of existing arsenic removal adsorbents are not satisfactory.In order to improve the adsorption capacity and regeneration performance of adsorbent,the magnetically core-shell arsenic adsorbent was prepared by using Fe3O4 as the magnetically core and Zr O2 as the outer layer adsorption material.The arsenic removal performance and regeneration performance of the adsorbent were investigated.Using ferric chloride as the iron source,anhydrous sodium acetate as auxiliary and glycol as solvent,Fe3O4 magnetically core was synthesized by solvent heat method,and were tested by TEM,SEM and BET.Then,the molar ratio of each material in the preparation of the arsenic adsorbent Fe3O4@Zr O2 was determined:N-butanol zirconium:PEG-2000:TMAOH:ethyl alcohol=1.1:0.1:3.8:610;after that,in the process of preparing adsorbent Fe3O4@Si O2@Zr O2,the molar ratio of material in the process of silicon coating was also determined: TEOS:PEG-2000:TMAOH:ethyl alcohol=2.69:0.1:0.95:548 and the molar ratio of material in process of zirconium coating was: N-butanol zirconium:PEG-2000:TMAOH:ethyl alcohol=1.1:0.1:3.8:610;finally,the synthetic conditions of magnetically core-shell arsenic adsorbent were determined.Three isothermal adsorption models: Langmuir model,Freundlich model,and Redlich-Peterson model were used to fit the experimental data of isothermal adsorption of different valence arsenic ions by different arsenic adsorbents.The results showed that the fitting maximum adsorption capacity of removal pentavalent arsenic and trivalent arsenic by D-1 are 22.37mg/g and 13.73mg/g respectively,and the fitting maximum adsorption capacity of removal pentavalent arsenic and trivalent arsenic by D-2 are 35.69mg/g and 16.93mg/g respectively.The fitting maximum adsorption capacity of removal pentavalent arsenic and trivalent arsenic by S-1 are24.30mg/g and 12.96mg/g respectively,and the fitting maximum adsorption capacity of removal pentavalent arsenic and trivalent arsenic by S-2 are 30.22mg/g and14.91mg/g respectively.The adsorption process is mainly chemical adsorption and isnot an ideal and single layer uniform adsorption.The adsorption efficiency is better under acidic condition;the chlorine ion has little effect on the adsorption process;the sulfate and phosphate have significant effects on the removal of arsenic.Taking a mine waste water as an example,the treatment of actual arsenic-contaminated water by preparing adsorbents were studied.The results show that the adsorbent can effectively remove arsenic in water.The adsorbent S-2 can reduce the total arsenic in actual waste-water from 0.710mg/L to 0.090mg/L and the removal rate is 87.32%,meeting the limit value of total arsenic in pollutants discharge Standard of Urban sewage treatment Plant.When sodium hydroxide was used as regeneration reagent,after five times of adsorption regeneration,the removal rate of actual arsenic-containing water by adsorbent still was 81.69% and the regeneration performance of adsorbent was excellent.