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改性柚皮生物炭的制备及其对水体磷酸盐的吸附性能

Preparation of Modified Pomelo Peel Biochars and Its Phosphate Removal Performance in Aqueous Solution

  • 摘要: 针对地表水体磷污染问题,利用农业废弃物柚子皮为原料制备柚皮生物炭(PB),以十六烷基三甲基溴化铵(CTMAB)为分散剂,制备改性纳米零价铁生物炭吸附材料(CNZVI)。使用扫描电镜、比表面积分析仪和X射线衍射分析仪等手段,研究柚皮生物炭改性前后的理化性能,并分析溶液pH、吸附剂投加量、反应时间、初始浓度和温度对CNZVI-PB吸附水中磷酸盐的影响。结果表明:CNZVI-PB对水中磷酸盐具备较好的吸附去除能力;溶液pH对磷吸附过程影响较大,最优吸附效率的pH值为3.0~7.0;该吸附反应是一个吸热过程,反应过程符合准二级动力学模型,及Langmuir等温吸附模型,在20~40℃时,磷最大吸附量达到8.47~9.62mg/g。CNZVI-PB对磷酸盐的吸附过程主要包括静电吸附和配位基交换作用。

     

    Abstract: To deal with the phosphate pollution in surface water, CNZVI-PB was prepared with pomelo peel biochars (PB) modified by nano zero- valent iron (NZVI) and cetyl trimethyl ammonium bromide (CTMAB). Physical and chemical properties of the new complex adsorbent material (CNZVI-PB) were analyzed with scanning electron microscope (SEM), specific surface area analyzer (BET), and X-ray diffraction analyzer (XRD). Meanwhile the effects of CNZVI-PB on phosphate adsorption were carried out in terms of pH, dosage of the adsorbent, shaking time, initial concentration, and temperature. Results showed that CNZVI-PB was effective for phosphate removal from aqueous solution. The adsorption effect of phosphate on CNZVI-PB relied on pH, and the optimal pH among 3.0-7.0. Moreover, it was an endothermic process, and the pseudo-second-order kinetic model fitted the phosphate kinetic experimental data well. The equilibrium isotherm data of phosphate adsorption onto the CNZVIPB could be described by the Langmuir isotherm model, and the maximum phosphate adsorption capacities were 8.47-9.62 mg/g at 20-40 ℃. The adsorption mechanism of phosphate on the CNZVI-PB mainly included the electrostatic attraction and ligand exchange interaction.

     

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