%0 Journal Article
%A HU Yuan
%A LIN Li
%A HU Yan-ping
%A LI Rui
%T Selecting Ferric Chloride as an Environmental-friendly Washing Agent for Heavy Metal Cadmium in Farmland Soil
%D 2019
%R 10.11988/ckyyb.20180145
%J Journal of Yangtze River Scientific Research Institute
%P 23-28
%V 36
%N 9
%X Soil washing is an effective approach for the remediation of heavy metal contaminated soil. Soil washing agent is a crucial factor which directly affects the efficiency of washing. We examined the performances of four washing agents, inclusive of acetic acid, citric acid, CaCl<sub>2</sub>, and FeCl<sub>3</sub>, in purifying farmland soil slightly contaminated by Cadmium (Cd) and the influential factors. We found that the effect of FeCl<sub>3</sub> is the optimum, followed by citric acid, acetic acid, and CaCl<sub>2</sub> in sequence.The H<sup>+</sup> hydrolyzed from the exchange between Fe<sub>3</sub><sup>+</sup>  from FeCl<sub>3</sub> solution and Cd<sup>2+</sup> from the soil stimulated the dissolution of carbonate bounded form of Cd; Cl<sup>-</sup> together with Cd<sup>2+</sup> could also form a stable chelate. In  optimized operation condition (solid-liquid ratio at  1∶5, and washing for 4 hours), the maximum removal rate of Cd was 30.24%, 24.62%,24.82%, and 81.90% by acetic acid, citric acid, CaCl<sub>2</sub>, and FeCl<sub>3</sub>, respectively. The pH value of soil had large impact on the washing effect. Apart from CaCl<sub>2</sub>,the washing effects of the other three washing agents all declined with the rising of pH value within 2.5-5.0, among which the washing effect of FeCl<sub>3</sub> underwent the most severe decline.
%U http://ckyyb.crsri.cn/EN/10.11988/ckyyb.20180145