麦秆黄原酸酯的合成条件优化及其在去除沼液中重金属的应用

The Optimization of Straw Xanthates′ Synthesis Condition and the Application in Elimination of Heavy Metal Ions from Biogas Slurry

以麦秸秆为原料制备黄原酸酯类吸附剂,用以处理沼液中的重金属,通过正交实验考察了各种制备因素对铜离子去除率的影响,同时比较了两种用于去除沼液中重金属的工艺流程。结果表明,麦秆黄原酸酯的最佳合成条件为：5g麦秸秆,加入浓度25%的NaOH、0.2mLCS2、25mL1%的硫酸镁,黄化时间3h。沼液中4种重金属的去除率为50.62%~95.27%,去除顺序为Cd〉Zn〉Pb〉Cu。多级过滤明显优于单级过滤,利用所设计的多级过滤滤柱,成功将废水中重金属浓度处理至工业废水排放标准。

The present research took wheat straw, which is commonly available in the rural area, as raw material to prepare xanthate floccu- lants for the disposal of heavy metal ions in wastewater. Through the orthogonal experimental design method[L2（554）], the best xanthates syn- thetic condition was determined as follows：5 g straw correspond to the concentration of sodium hydroxide 25%, the amount of carbon disul- fide 0.2 mL, carbon disulfide reaction time 3.0 h, and the amount of 1% magnesium chloride 25 mL. Subsequently, two optimal technological approaches（monolayer and multilayer treatment）with xanthate were designed and compared： The prepared xanthate flocculants were applied to remove the heavy ions contained in the biogas slurry after one time anaerobic treatment as well as that in the wastewater after three times anaerobic treatment. The results showed that the removal efficiency of the four kinds of heavy ions（Pb, Zn, Cd, Cu）in wastewater is dependent on the technological process. The multilayer process is more efficient than single-layer process：The removal rate in multilayer process is from 50.62% to 95.27%,and removal order is Cd〉Zn〉Pb〉Cu. Eventually, the treated biogas slurry can reach the industrial discharge stan- dard by using our multistage filter column. These results indicated that xanthate prepared by wheat straw has promising prospect in removing heavy metal ions from wastewater, and has some guiding significance on the reuse of biogas slurry.