Wu Zhen, Zhang Xian, Pang Jinglin, Zhang Xianming, Li Juan, Li Jiding, Zhang Panyue
Department of Chemical Engineering, Ordos Institute of Technology, Ordos 017000, China.
Department of Water Resources & Environmental Treatment, Redbud Innovation Institute, Ordos 017000, China.
ACS Omega. 2020 Jul 2;5(27):16413-16420. doi: 10.1021/acsomega.0c00532. eCollection 2020 Jul 14.
Polyaluminum chloride with a dominant species of Al (PAC-Al) was prepared in laboratory and used for humic acid (HA) removal from water. The action properties and mechanisms of PAC-Al, HA, calcium, and kaolin were tested and discussed. The results showed that the existence of calcium or kaolin contributed to the HA removal when the PAC-Al dosage was deficient and had no obvious effect when the amount of PAC-Al was sufficient. When the PAC-Al dosage was 0.01 and 0.02 mmol/L, the HA removal rate was increased by 66.59 and 42.20%, respectively, with a calcium concentration of 2.0 mmol/L, or increased by 53.31 and 40.92%, respectively, with the kaolin particle concentration of 150 mg/L. Calcium could compress the double electrical layers or complex with HA to neutralize a part of the surface negative charge of HA, but could not make the water system reach its isoelectric point. The mechanisms of calcium and kaolin's promoting coagulation effect were adsorption neutralization and collision aggregation respectively, but these actions were much weaker than that of PAC-Al with HA. The adsorption neutralization capacity of PAC-Al was calculated to be nearly 60 times than that of calcium, and the higher γ value of calcium modified by the Sips equation may indicate that the adsorption or neutralization sites of calcium on HA were pickier than PAC-Al
在实验室制备了以Al为主导物种的聚合氯化铝（PAC-Al），并将其用于去除水中的腐殖酸（HA）。对PAC-Al、HA、钙和高岭土的作用特性及作用机制进行了测试和讨论。结果表明，当PAC-Al投加量不足时，钙或高岭土的存在有助于HA的去除，而当PAC-Al投加量充足时则无明显影响。当PAC-Al投加量为0.01和0.02 mmol/L时，钙浓度为2.0 mmol/L时，HA去除率分别提高了66.59%和42.20%，高岭土颗粒浓度为150 mg/L时，HA去除率分别提高了53.31%和40.92%。钙可以压缩双电层或与HA络合以中和HA表面一部分负电荷，但不能使水体系达到其等电点。钙和高岭土促进混凝效果的机制分别是吸附中和和碰撞凝聚，但这些作用远弱于PAC-Al与HA的作用。计算得出PAC-Al的吸附中和能力约为钙的60倍，用Sips方程修正的钙的较高γ值可能表明钙在HA上的吸附或中和位点比PAC-Al更挑剔。
