人工湿地系统中填充基质对磷的吸附能力

Phosphorus Adsorption Capacity of Filter Media in Constructed Wetlands

人工湿地中填充基质对磷的吸附、沉淀作用是湿地系统的主要除磷机制,探明基质对磷的吸附能力对人工湿地系统设计至关重要.分别利用吸附试验和柱吸附试验考察了宝钢钢渣、首钢钢渣、水淬渣和陶粒4种基质对磷的吸附能力,同时进行了浸出液毒性鉴别试验.吸附试验表明,基质对磷的吸附符合Langmuir和Freundlich模型（R2为0.956～0.989）,采用Langmuir模型预测的基质磷吸附量为2.274～3.637 mg/g.在为期144 d的柱吸附试验中,填充宝钢钢渣和首钢钢渣的试验柱对磷有良好的去除效果,而填充水淬渣和陶粒的试验柱在90 d左右达到吸附饱和状态.在试验期内,基质的累积磷吸附量：宝钢钢渣为7.921 mg/g,首钢钢渣为7.495 mg/g,水淬渣3.317 mg/g,陶粒为1.627 mg/g.浸出液毒性鉴别试验表明,4种基质均有较高的环境安全性,由于2种钢渣和水淬渣具有较高的磷去除效率和便宜的价格,在湿地系统中具有广泛的应用价值.

Adsorption and precipitation of phosphorus（P） on filter media is a major P removal mechanism in constructed wetlands.Therefore,determining the P adsorption capacity of filter media is vital to the design of wetland systems with high P removal efficiency.Adsorption and column experiments were conducted to discover the P adsorption capacity of four filter media.Meanwhile,extraction toxicity identification of the filter media was carried out to ensure the safety of the media.The adsorption experiment showed that the Langmuir and Freundlich models described the adsorption data well（R2= 0.956-0.989）,with an estimated P adsorption capacity by the Langmuir model between 2.274 and 3.637（mg/g）.During the 144 days column experiment,the columns filled with Baogang and Shougang slags had relatively higher removal rates,while the columns filled with Shuicui slag and zeolite reached P saturation after about 90 days.The accumulated P adsorption capacity from the column experiment was as follows： Baogang slag 7.921 （mg/g）,Shougang slag 7.495（mg/g）,Shuicui slag 3.317（mg/g） and zeolite 1.627（mg/g）.Due to their high removal efficiency and low cost,the Baogang,Shougang and Shuicui slags have potential to be widely utilized in the wetland system.