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研究以钢铁厂酸洗废弃物磷酸渣为重金属镉吸附剂,旨在拓宽磷酸渣的综合利用途径。结果表明,重金属浸出毒性实验结果显示磷酸渣各有毒重金属浸出含量达标,对环境不会产生二次重金属污染。准2级动力学模型与实验数据具有良好的相关性,相关系数为0.999 9,表明磷酸渣吸附镉的过程是以化学反应为主导的过程;等温线模型表明在吸附过程中镉在磷酸渣表面发生均相反应,由Langumiur模型计算得磷酸渣的最大吸附容量为51.7 mg/g,与其它固废基吸附材料相比具有一定优势;吸附过程是可自发进行的吸热过程,整个过程体系混乱度增加。XRD和SEM等仪器对比分析镉吸附前后发现晶体组成与表面形貌并无明显变化,但吸附后的磷酸渣有Cd元素被检出,结合D-R模型结论可推测磷酸渣吸附Cd~(2+)的主要机理为离子交换。
In order to broaden the comprehensive utilization of phosphoric acid slag, the phosphate slag from pickling waste of iron and steel plant is taken as heavy metal cadmium adsorbent. The results showed that the leaching toxicity of heavy metals showed that the content of toxic heavy metals leached by phosphoric acid slag reached the standard, and no secondary heavy metal pollution would be caused to the environment. The quasi-second-order kinetic model has good correlation with the experimental data, and the correlation coefficient is 0.999 9, indicating that the process of cadmium adsorption by phosphoric acid slag is dominated by chemical reaction. The isotherm model indicates that cadmium is adsorbed on the surface of phosphate slag The maximum adsorption capacity of phosphoric acid slag calculated by Langumiur model is 51.7 mg / g, which has certain advantages compared with other solid-based adsorbents. The adsorption process is a spontaneous endothermic process, and the whole process is chaotic Degree increased. The results of XRD and SEM showed that there was no obvious change in crystal composition and surface morphology before and after cadmium adsorption. However, Cd element was detected in the phosphate residue after adsorption. Combined with the conclusion of DR model, The main mechanism is ion exchange.