Equilibrium and Kinetic Studies of Phosphate Adsorption Onto Corn Straw Char Supported Nano Ferric Oxide Composite
Equilibrium and Kinetic Studies of Phosphate Adsorption Onto Corn Straw Char Supported Nano Ferric Oxide Composite
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DOI：
10.1166/sam.2015.2397
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发表时间：
2015
期刊：
影响因子：
--
通讯作者：
and Shiqiang Wei;Zhenmao Jiang;Hongguang Zhou
中科院分区：
文献类型：
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作者：
and Shiqiang Wei;Zhenmao Jiang;Hongguang Zhou
以农业固体废弃物玉米秸秆为原料制备了纳米FeOOH复合生物质焦，研究了其对水中磷酸盐的去除效果。采用“热解-金属络合物阴离子澄清-沉淀”的方法制备了复合半焦。在不同条件下得到的复合材料的饱和吸附容量为28.8 ~ 37.3 mg P/g。提高升温速率或升温终温均会降低复合吸附剂的吸附容量。在pH = 3 ~ 6范围内，去除率最高。吸附量随吸附温度的升高而增大，随pH值的升高而减小。吸附平衡数据符合Langmuir和Freundlich等温式，Freundlich方程中n-1值在0 ~ 1之间，表明吸附较强。吸附动力学数据符合准二级动力学模型，吸附过程以化学吸附为主。即使在非常高浓度的添加剂离子水平下，优异的吸附能力以及低解吸率进一步支持磷酸盐与复合材料之间发生化学吸附。因此，吸附机制可能涉及离子交换和化学吸附。
Phosphate removal from aqueous solution was investigated using nano-FeOOH composite biomass char developed from corn straw, an agricultural solid waste. The composite char was obtained by a procedure of “pyrolysis–metal complex anion incorporation-precipitation.” The saturated adsorption capacity of composite obtained under different conditions varied 28.8∼37.3 mg P/g. Either higher final temperature or higher heating rate may decrease the adsorption capacity of composite absorbents. The removal efficiency reached maximum in the pH range of 3∼6. Adsorption capacity increased with the adsorption temperature increasing and decreased with pH increasing. The adsorption equilibrium data well followed both Langmuir and Freundlich isotherms, and the constant n –1 values in Freundlich equation between 0 and 1 indicated a strong adsorption. The adsorption kinetics dada following pseudo-second-order model indicated that the adsorption process was dominated by chemisorption. The excellent adsorption ability even at very high concentrate additive ions level as well as the low desorption ratio further supported the occurrence of chemisorption between phosphate and the composite. Thus, the adsorption mechanisms may involve both ion exchange and chemisorption.