多核聚合形态Al30混凝控制水中腐殖酸与残留铝的研究

制备了优势形态为Al30的聚合铝PAC-Al30,与优势形态为Al13的常用聚合铝PAC-Al13及AlCl3作对比实验,考察了不同铝系混凝剂强化混凝控制水中腐殖酸(Humic Acid,HA)和残留铝的差异.结果表明,PAC-Al30具有足够的稳定性,与PAC-Al13和AlCl3相比,PAC-Al30可以更好地控制出水腐殖酸和残留铝浓度,且以碱化度B为2.4的PAC-Al30效果最好.PAC-Al30和PAC-Al13比AlCl3有更宽的有效投量范围,可以提高实际应用中的稳定性.Ca2 和高岭土的存在均有利于PAC-Al30混凝去除HA.低温对PAC-Al30混凝去除HA有不利影响.研究表明,Al30是一种可用于控制水中腐殖酸和残留铝的新型混凝/絮凝活性成分.

Ways to control humic acid and residual aluminum in water by means of coagulation with polynuclear species Al30

The present article introduces the method for preparing polyaluminum chlorides PAC-Al30 with a high Al30 content.We have examined the coagulation behaviors and effects of PAC-Al30 in controlling humic acid and residual aluminum in water.The results show that PAC-Al30 enjoys sufficient stability in 90 d.In comparing AlCl3 and polyaluminum chloride PAC-Al13 with a high Al13 content,PAC-Al30 has obvious advantages in controlling humic acid and residual aluminum in water with a coagulant dosage lower than 0.04 mmol/L.In addition,PAC-Al30 and PAC-Al13 have a broader dosage range for efficient coagulation than AlCl3,which helps them to better their own feasibility in practice.The behaviors and coagulation effect of PAC-Al30 can be improved with the increase of B value;However,the restabilization dosage would probably be reduced with the increase of B value.Furthermore,the effluence of coagulation with PAC-Al30 on pH of samples is weaker than that with PAC-Al13 and stronger than that with AlCl3.The presence of 1 mmol/L Ca2+ in water actually benefits HA removal and residual aluminum decrease due to the PAC-Al30 coagulation,especially when the PAC-Al30 dosages were lower than 0.02 mmol/L.With a kaolin concentration of 100 mg/L,PAC-Al30 would display a significant improvement for HA removal and residual aluminum reduction.However,low temperatures are disadvantageous to the HA removal by PAC-Al30 coagulation.Last of all,Al30 is proved to be a new active species for coagulation-flocculation to remove HA from water.