Yu Jian, Liang Wenyan, Wang Li, Li Feizhen, Zou Yuanlong, Wang Haidong
College of Environmental Science and Engineering, Beijing Forestry University, Beijing 100083, China; National Center for Rural Water Supply Technical Guidance, Chinese Center for Disease Control and Prevention, Beijing 102200, China.
College of Environmental Science and Engineering, Beijing Forestry University, Beijing 100083, China.
J Environ Sci (China). 2015 May 1;31:81-8. doi: 10.1016/j.jes.2014.12.007. Epub 2015 Mar 25.
This study was performed to investigate the removal of phosphate from domestic wastewater using a modified steel slag as the adsorbent. The adsorption effects of alkalinity, salt, water, and thermal modification were investigated. The results showed that thermal activation at 800°C for 1 hr was the optimum operation to improve the adsorption capacity. The adsorption process of the thermally modified slag was well described by the Elovich kinetic model and the Langmuir isotherm model. The maximum adsorption capacity calculated from the Langmuir model reached 13.62 mg/g. Scanning electron microscopy indicated that the surface of the modified slag was cracked and that the texture became loose after heating. The surface area and pore volume did not change after thermal modification. In the treatment of domestic wastewater, the modified slag bed (35.5 kg) removed phosphate effectively and operated for 158 days until the effluent P rose above the limit concentration of 0.5 mg/L. The phosphate fractionation method, which is often applied in soil research, was used to analyze the phosphate adsorption behavior in the slag bed. The analysis revealed that the total contents of various Ca-P forms accounted for 81.4%-91.1%, i.e., Ca10-P 50.6%-65.1%, Ca8-P 17.8%-25.0%, and Ca2-P 4.66%-9.20%. The forms of Al-P, Fe-P, and O-P accounted for only 8.9%-18.6%. The formation of Ca10-P precipitates was considered to be the main mechanism of phosphate removal in the thermally modified slag bed.
本研究旨在探讨以改性钢渣为吸附剂去除生活污水中磷的效果。研究了碱度、盐分、水和热改性对吸附效果的影响。结果表明，800℃热活化1小时是提高吸附容量的最佳操作条件。热改性钢渣的吸附过程可用埃洛维奇动力学模型和朗缪尔等温线模型很好地描述。根据朗缪尔模型计算出的最大吸附容量达到13.62mg/g。扫描电子显微镜表明，改性钢渣加热后表面出现裂纹，质地变得疏松。热改性后比表面积和孔容未发生变化。在处理生活污水时，改性钢渣床（35.5kg）能有效去除磷，运行158天直至出水磷含量升至0.5mg/L的限值浓度以上。采用常用于土壤研究的磷分级方法分析钢渣床中的磷吸附行为。分析表明，各种钙磷形态的总含量占81.4%-91.1%，即Ca10-P占50.6%-65.1%，Ca8-P占17.8%-25.0%，Ca2-P占4.66%-9.20%。铝磷、铁磷和有机磷形态仅占8.9%-18.6%。Ca10-P沉淀的形成被认为是热改性钢渣床中磷去除的主要机制。
