| 镁改性硅藻土回收废水氮磷产物对水中Pb2+和Zn2+的去除 |
| 摘要点击 1297 全文点击 458 投稿时间：2022-03-07 修订日期：2022-04-15 |
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| 中文关键词 硅藻土 鸟粪石 氮磷回收 重金属 吸附 |
| 英文关键词 diatomite struvite nitrogen and phosphorus recovery heavy metal adsorption |
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| 中文摘要 |
| 通过使用镁改性硅藻土回收废水中的氮磷营养素，优化制备了一种复合材料（D-MAP），并将其用于废水中重金属Pb2+和Zn2+的去除.研究探讨了材料投加量、反应时间、反应温度和溶液初始pH等因素对Pb2+和Zn2+在D-MAP上吸附的影响.D-MAP吸附去除Pb2+和Zn2+的最优条件为：D-MAP投加量分别为0.25 g·L-1和0.30 g·L-1，Pb2+和Zn2+初始浓度分别为300 mg·L-1和60 mg·L-1，溶液初始pH为5.0.在此条件下，其对Pb2+和Zn2+去除率分别可达78.67%和89.66%.动力学和热力学的结果表明，D-MAP对Pb2+和Zn2+的吸附更符合准二级动力学模型；其吸附等温线可用Langmuir模型描述，吸附是自发吸热的过程.Langmuir等温拟合结果指出，D-MAP对Pb2+和Zn2+的最大吸附容量分别为901.0 mg·g-1和206.2 mg·g-1.使用SEM/EDS、XRD和FT-IR等手段对吸附Pb2+和Zn2+前后的吸附剂进行表征，结果表明，D-MAP是一种鸟粪石-硅藻土复合材料，可通过与Pb2+和Zn2+生成Pb10（PO4）6（OH）2和Zn3（PO4）2·2H2 O去除废水中Pb2+和Zn2+.D-MAP对Pb2+和Zn2+的去除效果随着pH的增加而增加，且最终产物形态随pH不同产生变化. |
| 英文摘要 |
| By using magnesium-modified diatomite to recover nitrogen and phosphorus nutrients from wastewater, a composite material (D-MAP) was applied to remove the heavy metal ions Pb2+and Zn2+ in wastewater. The effects of material dosage, reaction time, reaction temperature, and initial pH of the solution on the adsorption of Pb2+ and Zn2+ on D-MAP were studied. The optimum conditions were as follows:the dosage of D-MAP was 0.25 g·L-1 and 0.30 g·L-1, the initial concentrations of Pb2+ and Zn2+ were 300 mg·L-1 and 60 mg·L-1, and the initial pH of the solution was 5.0. Under these conditions, the removal rates of Pb2+ and Zn2+ reached 78.67% and 89.66%. The results of kinetics and thermodynamics showed that the adsorption of Pb2+ and Zn2+ by D-MAP was more consistent with the quasi-second-order kinetic model, and the adsorption isotherm was described by the Langmuir model. The adsorption was a spontaneous endothermic process, and the maximum adsorption capacities for Pb2+ and Zn2+ were 901.0 mg·g-1 and 206.2 mg·g-1, respectively. The adsorbents before and after adsorption of Pb2+ and Zn2+ were characterized by SEM/EDS, XRD, and FT-IR. The results showed that D-MAP was a struvite-diatomite composite, which could be combined with Pb2+ and Zn2+ to form Pb10(PO4)6(OH)2 and Zn3(PO4)2·2H2O. The removal efficiency of Pb2+ and Zn2+ by D-MAP increased with the increase in pH, and the morphology of the final product changed with differing pH. |
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