煤气化细渣制备碳硅复合材料吸附去除水中Pb^(2+)

Adsorption of Pb^(2+) from water by carbon-silica composite prepared from coal gasification fine slag

以煤气化细渣为原料制备了高比表面积碳硅复合材料,并利用过硫酸铵对其进行表面改性,用于吸附100.0 mg/L PbCl_2溶液中Pb^(2+)。表征结果显示:碳硅复合材料的比表面积为1 347 m^2/g,改性后降为474 m2/g;改性后材料表面的羟基、羰基和羧基等含氧基团的含量显著增加。实验结果表明:溶液pH为5时,改性碳硅复合材料对Pb^(2+)的平衡吸附量为124 mg/g,Pb^(2+)去除率可达98.2%;吸附过程符合准二级动力学模型,以化学吸附为主,伴有物理吸附;吸附过程分为外扩散和内扩散两个阶段,受内扩散控制。

The carbon-silica composite with a high surface area was prepared using coal gasification fine slag as raw material and oxidized by ammonium persulfate for surface modification to absorb Pb2+ from PbCl2 solution ( 100.0 mg/L ). The characterization results indicated that : The BET surface area of the carbon-silica composite was 1 347 m2 /g and deceased to 474 m2 /g after modification;The amounts of oxygen-containing functional groups on the material surface , such as hydroxyl , carbonyl and carboxyl , increased significantly after modification. The experimental results showed that : When the solution pH was 5 , the equilibrium adsorption capacity of Pb2+ on modified carbon-silica composite reached 124 mg/g and Pb2+ removal rate was 98.2 %;The adsorption process followed the pseudo-second-order kinetics model and was mainly chemical adsorption , accompanied by physical adsorption;The adsorption process was divided into two adsorption stages of external diffusion and internal diffusion , and was controlled by internal diffusion.