废水中的钙离子
(中南大学 冶金科学与工程学院，长沙 410083)
摘 要: 采用剩余污泥与人造沸石复合体系去除废水中的Ca2+，考察了各因素对Ca2+去除的影响。结果表明：沸石与废水的固液比是影响Ca2+去除的最关键因素，温度和pH值的影响较大，而反应时间在最初10 min内影响显著，之后则影响较小；在25 ℃，初始pH值8.04条件下，反应1 h，Ca2+的去除率随着固液比的增加而增大，初始Ca2+的质量浓度为801.60 mg/L时，保持沸石与废水固液比为3׃100，Ca2+的去除率达到80.38%，剩余Ca2+仅为157.31 mg/L；升高温度对Ca2+去除有促进作用，Ca2+的去除率从20 ℃时的77.30%增大到45 ℃时的90.71%；Ca2+去除在最初的50 min内吸附达到平衡。人造沸石的红外光谱图表明脱钙过程主要是化学吸附。
关键字: 剩余污泥；人造沸石；钙离子；废水净化
sludge and artificial zeolites
（School of Metallurgical Science and Engineering, Central South University, Changsha 410083, China）
Abstract: Removal of calcium from wastewater was carried out using waste activated sludge and artificial zeolites. The effects of parameters such as pH, temperature, reaction time and sorption duration on removal rate of Ca2+ were studied. The results show that solid-to-liquid ratio is the most important factor on the removal of Ca2+, pH and temperature have obvious influences on the process, and reaction time has little effect on removal rate of Ca2+ after reacting for 10 min. The removal rate of Ca2+ increases with increasing solid-to-liquid ratio under conditions of 25 ℃, initial pH 8.04, reacting for 1 h. 80.38% of the initial Ca2+ content (solution containing 801.60 mg/L of Ca2+) is removed under condition of solid-to-liquid ratio of 3׃100, and terminal concentration of Ca2+ of 157.31 mg/L. The increase of temperature is advantageous to the removal of Ca2+, the removal rate of Ca2+ rises from 77.30% to 90.71% with temperature enhancing from 20 ℃ to 45 ℃. The removal of Ca2+ is finished in 50 min. According to the IR spectrum of artificial zeolite, chemical biosorption takes main effect on the removal of Ca2+.
Key words: waste activated sludge; artificial zeolites; Ca2+; wastewater purify
