改性钙基吸附剂对垃圾焚烧模拟烟气中镉的吸附研究

采用不同的改性方法对轻质碳酸钙进行改性,制得一系列改性钙基吸附剂,利用BET、XRD和AESEDS等方法研究其理化性能,并在垃圾焚烧模拟烟气条件下验证了改性钙基吸附剂对重金属镉的吸附性能.结果表明,高温热活化方法所得的产品为CaO,其比表面积从7.34m2·g-1增加到18.27m2·g-1,盐浸泡煅烧所得的产品为CaONaCl共晶体,其层间距比CaO增大了0.03193nm,具有良好的表面活性和孔隙结构;与轻质碳酸钙相比,改性钙基吸附剂对镉的吸附效果明显提高;CaO的吸附机理主要以物理吸附为主,CaONaCl则以化学吸附为主.

Cd vapor adsorption of modified calcium-based adsorbents in simulated MSW flue gases

A series of calcium-based adsorbents were prepared from light calcium carbonate by various modification methods. The physical characteristics of the modified substrates were inspected using BET specific area analyzer, XRD, and AES-EDS spectra. Their adsorption capacities for Cd were examined by introducing CdCl2 vapor into a flue gas system simulating waste incineration. The results showed that the main product after thermal treatment was CaO and the BET specific area of CaO increased dramatically from 7.34 m2?g-1 to 18.27 m2?g-1 after the treatment. The product of salt soaking-calcination was eutectic CaO/NaCl and the interlayer distance between the eutectic layers was 0.03193 nm larger than that of CaO crystal. Therefore, the eutectic CaO/NaCl had high surface activity and developed pore structure. The Cd adsorption capacities of the modified products were also greatly improved compared to light calcium carbonate. The main mechanism of Cd adsorption was physical sorption for CaO, and chemical adsorption for CaO/NaCl.