响应曲面法优化低品位铁尾矿负载壳聚糖处理含Cd^(2+)废水实验

Response Surface Method to Optimize the Treatment of Cd^(2+)-Containing Wastewater with Low-Grade Iron Tailings Loaded with Chitosan

这是一篇矿物材料与环境工程领域的论文。本文以含镉废水为研究对象,采用低品位铁尾矿负载壳聚糖作为吸附剂,对比了低品位铁尾矿负载壳聚糖前后对Cd^(2+)的吸附效果,结果表明,复合吸附剂的吸附效果优于低品位铁尾矿吸附剂;同时采用Box-Behnken Design(BBD)响应曲面法设计实验,以镉离子吸附率(Q)作为响应值,通过考查初始pH值(A)、吸附剂加入量(B)和吸附时间(C)三个影响因素对低品位铁尾矿负载壳聚糖吸附除镉的单独和交互作用,建立了低品位铁尾矿负载壳聚糖与镉离子影响因素的非线性二次多元回归预测模型:Q=86.16+14.68×A+5.21×B+1.36×C-1.98×A×B-1.54×A×C-0.46×B×C-6.75×A^(2)+0.12×B^(2)+1.25C^(2),并获得了较佳优化的吸附实验条件。结果表明,复合吸附剂对Cd^(2+)吸附率影响因子的主次顺序为初始pH值>吸附剂加入量>吸附时间。当初始pH值为8.00,吸附剂加入量25.00 g/L,吸附时间15 min,初始Cd^(2+)浓度为30 mg/L,吸附温度为25℃左右的较佳条件下,得到Cd^(2+)较大吸附率的预测值为99.33%,实验值为99.16%,实验值与预测值基本一致,说明该模型用于Cd^(2+)吸附优化模型合理,其优化条件可行。

This is a paper in the field of mineral materials and environmental engineering.In this paper,cadmium-containing wastewater was used as the research object,and low-grade iron tailings loaded with chitosan was used as the adsorbent to compare the adsorption effect of low-grade iron tailings on Cd^(2+)before and after loading chitosan.The results showed that the adsorption effect of the composite adsorbent better than low-grade iron tailings adsorbent;At the same time,the Box-Behnken Design(BBD)response surface method is used to design the experiment,and the cadmium ion adsorption rate(Q)is used as the response value.The initial pH value,the amount of adsorbent added and the adsorption time are investigated.The three influencing factors have separate and interactive effects on the adsorption and removal of cadmium by chitosan loaded on low-grade iron tailings,and a nonlinear quadratic multiple regression prediction model of the influencing factors of low-grade iron tailings loaded with chitosan and cadmium ions is established:Q=86.16+14.68×A+5.21×B+1.36×C−1.98×A×B−1.54×A×C−0.46×B×C−6.75×A^(2)+0.12×B^(2)+1.25C^(2),and got the better optimizedexperimental conditions for adsorption.The results show that the primary and secondary order of the influencing factors of the composite adsorbent on the Cd^(2+)adsorption rate is initial pH value>adsorbent added amount>adsorption time.When the initial pH value is 8.00,the amount of adsorbent added is 25.00 g/L,the adsorption time is 15 min,the initial Cd^(2+)concentration is 30 mg/L,and the adsorption temperature is about 25℃,the predicted value of the maximum adsorption rate of Cd^(2+)is 99.33%,the experimental value is 99.16%,and the experimental value is basically the same as the predicted value,indicating that the model is reasonable for the Cd^(2+)adsorption optimization model and its optimization conditions are feasible.