电厂粉煤灰、炉渣和污泥复合陶粒对低浓度Pb^(2+)的吸附特性

Adsorption Characteristics of Power Plant Fly Ash,Slag and Sludge Composite Ceramics for Low Concentration Pb^(2+)

针对重金属污染具有来源广、危害大等特点,通过以电厂废物(粉煤灰、炉渣)和脱水污泥为原料制备一种高效且价廉的陶粒吸附剂,采用吸附影响因素实验、解吸再生实验、吸附动力学模型和等温吸附模型的拟合以及陶粒表征分析,探究陶粒对Pb^(2+)的吸附特性,同时为实现废物资源化利用提供新思路.结果表明:陶粒去除Pb^(2+)的较佳吸附条件为粒径4 mm、pH 4.5~5.0、吸附时间360 min、吸附温度25℃.陶粒再生所用较佳解吸剂为0.5 mol/L的HCl溶液,较佳解吸时间和次数分别为120 min和5次,解吸5次后陶粒对Pb^(2+)的去除率为92.67%.此吸附过程更好地遵循了准二级动力学模型和Freundlich等温吸附模型.陶粒上的O-H、Si-O和金属氧化键在吸附Pb^(2+)的过程中起主要作用.陶粒吸附Pb^(2+)后,出现了新的物相Pb_(2)Cl_(3)OH和PbO,陶粒与Pb^(2+)之间发生化学吸附,为自发进行的放热反应.陶粒处理实际废水中Pb^(2+)的去除率可达93.70%,Pb^(2+)浓度由3.74 mg/L降至0.24 mg/L.研究显示,电厂粉煤灰、炉渣和污泥复合陶粒对Pb^(2+)具有一定的去除效果,可为以固体废物为原料制备的吸附剂在重金属废水处理应用中提供数据支撑.

Heavy metal pollution has the characteristics of wide sources and great harm.This study attempts to use power plant waste(fly ash,slag)and dewatered sludge to prepare efficient and inexpensive ceramic adsorbent.Through adsorption influencing factor experiments,desorption regeneration experiments,adsorption kinetic model and adsorption isotherm model fitting,and ceramsite characterization analysis,the adsorption characteristics of ceramsite for Pb^(2+) are explored,and at the same time,new ideas are provided for the realization of waste resource utilization.The results showed that the optimal conditions for Pb^(2+) removal by ceramic granules were as follows:particle size 4 mm,pH 4.5-5.0,adsorption time 360 min,adsorption temperature 25°C.The best conditions for the regeneration of ceramsite was 0.5 mol/L HCl solution,and the best desorption time and times were 120 min and 5 times,respectively.The removal rate of Pb^(2+) by the ceramsite after 5 times of regeneration was 92.67%.The adsorption process followed the pseudo-second-order kinetic model and the Freundlich adsorption isotherm model.The O-H,Si-O and metal oxidation bonds on the ceramsite played a major role in the adsorption of Pb^(2+).After the ceramsite adsorbed Pb^(2+),Pb_(2)Cl_(3)OH and PbO formed.Chemical adsorption occurred between the ceramsite and Pb^(2+),which was a spontaneous exothermic reaction.The removal rate of Pb^(2+) in the actual wastewater treated by ceramide could reach 93.70%,and the concentration of Pb^(2+) decreased from 3.74 mg/L to 0.24 mg/L.The study showed that the composite ceramic had a certain removal effect on Pb^(2+),which provided data support for the application of adsorbent prepared from solid waste in the treatment of heavy metal wastewater.