Studies On Factors Influencing Electrokintic Remediation Of Cd-polluted By Cd Under Low-voltage Electric Field

The wide use of heavy metal-containing feed additives on large-scale farms in our country to promote animals’ growth has led to elevated levels of heavy metals in animal feces.Heavy metal pollution happens when the feces enter soil and aquatic environments.Electrokinetic remediation as a green technique has some advantages such as easy installation,debugging and operability.This paper’ main contents and findings including the following:(1)The experiments about properties of fertilizer.Including the effects of different organic acids on Cd-parsing in the manure;The influence of different concentration of acetic acid on the fertilizer pH.The results showed that:Ratio of formic acid andcitric acid,acetic acid is more conducive to the promotion of manure’ cadmium resolution;Lower concentrations of acetic acid has little effect on pH change of manure,the pH of manure was suitably maintained around 7.(2)For Cd-residual manure,the pH of effluent from the anode area will be controlled with acetic acid,different test conditions,including 3 V,6 V,9 V,were analyzed in the experiences.The results showed that:The average rate of total Cd removal was 7.5%、10.82%、11.84%under different voltage,The level of ammonium nitrogen in the cathode liquid produced under 3 V was 172 mg/L,smaller than that under 6 V(302 mg/L)and 9V(421 mg/L),in other word,The loss of nitrogen from the manure during electrokinetic remediation was smaller under 6 V than under 9V.(3)Preteatmental experiental study on eletrokinetic remediationof Cd-polluted manure.diffe-rent test conditions,including whether acidified with acetic acid pretreatment and different manure acidification pretreatments(0,20 or 40 mmol/L acetic acid).The results showed that:Manure pretreatment with acetic acid improved Cd removal,and lowered the reactivity of Cd in manure.The levels of total Cd,and bioavailable Cd in the manure after electrokinetic treatment were reduced by 27.85%,29.2%,potential risk fell by 20.3%,18.4%on the environment,and by 11.76%,14.14%when the manure was pre-acidified with 20 and 40 mmol/L acetic acid,respectively,Due to the high organic content of organic fertilizer,is not conducive to the formation of ionized Cd,(4)Eletrokinetic remediation of Cd-polluted manure under soil adsorption media.Replacing the cathode half-area organic fertilizer with the soil,Soil adsorb ionized Cd from the anode migrate state.The results showed that:Cadmium accounted for 18.6%of migration from organic manure into the soil,and TN in the soil increased by 19.04%after experiment,Due to the adsorption of cathode area soil,The cathode of Cd in effluent can be ignored,the concentration of ammonium nitrogen in the effluent from the anode area up to 357mg/L,Wastewater can be used directly as a liquid nitrogen fertilizer。...