富磷废弃钙基生物炭对水体中铅的去除

基于磷酸盐和碳酸盐对铅的高亲和特性，将蛋壳与厨余垃圾煅烧制备的含钙生物炭除磷后（ES-BC/P），用于水体中铅的去除.结果表明，ES-BC/P在较优的投加量下对不同浓度的铅（1~100 mg·L^-1）均具有较好的去除性能，去除效率均高于99%，且反应后磷的释放量较低；ES-BC/P偏碱性，因含铅污染液呈弱酸性，ES-BC/P加入后无需调节体系的pH值即可达到较好的去除效果；反应动力学及等温线实验表明，ES-BC/P除铅主要为单层化学吸附，最大吸附容量为493.12 mg·g^-1（318 K）；表征分析结果表明，铅主要通过与ES-BC/P中的Ca-P化合物和CaCO₃进行反应，Pb²⁺可与Ca²⁺发生交换作用，形成 Pb₅（PO₄）₃OH、Pb₁₀（PO₄）₆（OH）₂、PbCO₃和Pb₃（CO₃）₂（OH）₂等沉淀而被去除.综上所述，除磷后的ES-BC材料可实现水体中铅的高效去除，从而实现废弃物的资源化利用.

Lead Removal from Water by Calcium-containing Biochar with Saturated Phosphate

Calcium-containing biochar （ES-BC） was prepared by pyrolyzing eggshell and kitchen wastes， and the ES-BC composite was used to remove phosphate （marked as ES-BC/P）. Based on the high affinity of phosphate and carbonate to lead， the ES-BC/P was then used to remove lead from the water. The results showed that， in the appropriate dosage， ES-BC/P could remove lead efficiently at different initial concentrations （1-100 mg·L^-1）， and the removal efficiency could reach to 99%. Meanwhile， the release of phosphorus could be ignored after the reaction. As ES-BC/P was alkaline， and the lead-containing solution was weakly acidic， the addition of ES-BC/P could adjust the pH of the system automatically. The reaction kinetics and isotherm experiments showed that the lead removal by ES-BC/P was mainly monolayer chemisorption with a maximum adsorption capacity of 493.12 mg·g^-1 （318 K）. The characterization results showed that lead was mainly removed through the ion exchanges of Pb²⁺ in the solution with Ca²⁺ in ES-BC/P. Then， the Pb²⁺ combined with CO₃^2- and PO₄^2- to form many precipitates， including Pb₅（PO₄）₃OH， Pb₁₀（PO₄）₆（OH）₂， PbCO₃， and Pb₃（CO₃）₂（OH）₂. In summary， the ES-BC/P material could achieve the efficient removal of lead from the water， thereby realizing the resource utilization of the wastes.