生物制剂法处理含锰废水新工艺研究

【作者】 裴斐；

【导师】 王云燕；

【作者基本信息】 中南大学 ， 环境工程， 2010， 硕士

【摘要】 电解二氧化锰是资源、能源消耗高,污染物产生量大的行业。其产生的含锰废水中含有大量的锰,直接排入水体,将会对水体、土壤等生态系统造成严重污染,带来一系列环境问题。目前普遍使用石灰中和水解法处理,但出水难以稳定达到排放标准。含锰废水的高效治理仍是重金属废水处理中关注的焦点。本研究在热力学研究及含锰废水特性分析的基础上,开发了生物制剂配合-水解法直接深度处理含锰废水新技术。在全面考虑锰离子在水中存在的各种羟合配离子的基础上,引入配位化学和水化学的有关理论,对Mn2+-H20体系中羟合配离子的热力学平衡进行详细全面的分析研究,并利用Pitzer理论计算了体系中不同离子强度下的活度系数,绘制不同离子强度下锰的各类配合离子浓度pc-pH图。根据配位化学热力学原理及Pitzer理论,绘制了298.15K下-lnγ±MnSO4 -I关系图及pc-pH图。-lnγ±MnSO4 -I图表明I从0.00到0.09时,-lnγ±MnSO4从0.00迅速增大到1.21；当0.00≤I≤1.69时,-lnγ±MnSO4变化很缓慢；I≥2.25时,-lnγ±MnSO4基本不变。pc-pH图表明Mn(OH)2(s)的最小溶解度随离子强度的增加而增加,当I由0.00增加到4.00时,pc由6.5减小到5.5；最小溶解度的pH也随离子强度增加而增加,离子强度由0.00增加到2.89时,pH由11.80增至12.76,I(I≤4.00)再增加,pH保持不变；不同离子强度下Mn(OH)2(s)的最小溶解度与相应的pH存在单值函数关系。在含锰废水特性分析的基础上,开发了生物制剂配合-水解法直接深度处理含锰废水新技术。含锰废水生物制剂配合体系中存在两个缓冲区,分别为pH值8.80-11.18和12.28-13.08。废水从pH值2.04升高至10.00左右,氢氧化钠的理论加入量为2.67-4.00g/L。生物制剂配合-水解法直接深度处理含锰废水优化工艺条件：生物制剂加入量控制生物制剂与废水中锰的质量比为0.2,配合时间5 min,水解时间5 min,温度25℃,pH值10.0,PAM加入量2 mg/L,可将废水中锰浓度从994 mg/L去除到0.127 mg/L,扩大实验结果出水中锰浓度为0.0651 mg/L,达到了《生活饮用水卫生标准》(GB5749-2006)的限值0.1 mg/L。正交试验的极差分析表明,影响生物制剂去除锰离子的各因素的主次顺序为：pH值>配位时间>生物制剂加入量>温度>PAM加入量>水解时间。沉渣SEM、EDS、XRD、IR分析结果表明：含锰沉渣呈无定型及棒状,主要物相为CaSO4,渣中锰含量达14.16%,可返回生产系统回收锰。生物制剂通过其中的-OH、-COOH、-NH、-C=O、-S03、-C-O(H)、C-Cl等基团与废水中的含锰离子配合,在水解的过程中形成难溶物质沉淀分离。现场工业试验结果确定了工业生产最优条件：生物制剂的投加量控制生物制剂与废水中锰的质量比为0.6,配位时间为40 min,水解时间60min、pH 10。最优化条件下的工业试验,净化水中锰离子的浓度为0.05 mg/L,远低于国家的一级排放标准2 mg/L,达到了《生活饮用水卫生标准》(GB5749-2006)的限值0.1 mg/L。处理成本与原水中锰离子的浓度成正比关系,但目前湘潭电化废水中Mn2+的平均浓度低于600 mg／L,生物制剂的药剂成本低于3元／吨。更多还原

【Abstract】 Electrolytic manganese dioxide (EMD) industry, with high resource and energy consumption, produces large quantities of industrial waste, such as manganese-containing wastewater. It contains large amounts of manganese and will destroy the food chain to risk human health as the wastewater is discharged directly into water body. The most commonly used method for treating the wastewater is lime neutralization-hydrolysis that involves adding alkali into acidic manganese-containing wastewater for the hydrolysis with manganese causing the generation of insoluble precipitate. However, it has difficulty in treating Mn2+ to achieve the Standard of National Discharge.In this study, the theory of coordination chemistry and the water chemistry were introduced to get a comprehensive analysis on thermodynamics balance of hydroxyl complex ions in the Mn2+-H2O system, and Pitzer theory was used to calculate activity coefficients in different ion intensity in the system. The pc-pH diagrams for all Mn2+ complex species with different ion intensity were obtained.Then "Direct and Deep Treatment of Manganese-containing Wastewater by Biologics Complexing-Hydrolyzation" was developed.Diagram of pc-pH representing the relationship between the concentration of Mn2+ complex ions and pH was plotted, also including the diagram of -ln/γ±MnSOt-I that shows the relationship between activity coefficient and ion intensity based on the thermodynamic principle of coordination chemistry and Pitzer theory at 298.15K. The diagram of -lnγ±MnSO4-I indicated that -lnγ±MnSO4 increased significantly from 0.00 up to 1.21 when I changed from 0.00 to 0.09;-lnγ±MnSO4 tended to increase slowly when I was between 1.00 and 1.69;-lnγ±MnSO4 nearly remained constant when I was ranged from 2.25 to 4.00.Diagrams of pc-pH illustrated that the minimum solubility of Mn(OH)2(s) increased with the increase of I, the pc increased from 6.5 to 5.5 when I increased from 0.00 to 4.00;The pH of the minimum solubility of Mn(OH)2(s) increased with the increase of I, the pH increased from 11.80 to 12.76 when Iincreased from 0.00 to 2.89,no change in pH was observed when I(I≤4.00) increased.It is possible there is uniform function relation between the minimum solubility of Mn(OH)2(s) and relevant pH in different ion indensity.A novel technology for the treatment of manganese-containing wastewater by biologics has been proposed based on the properties analysis of manganese-containing wastewater. There are two pH buffer zones (pH 8.80-11.18 and pH 12.28-13.08)in the complex system of manganese-containing wastewater and biologics.Theoretically, the required amount of sodium hydroxide for increasing pH value from 2.04 to 10.00 was 2.67-4.00 g/L. The optimum condition was 0.2 of mass ratio of biologics to manganese,5 min of cooperation time,5 min of hydrolysis time,25℃of temperature, pH 10.0,2 mg/L of PAM. Under the above optimum conditions,manganese concentration decreased from 994 mg/L to 0.127 mg/L in laboratory experiment.However, only 0.0651 mg/L of manganese remained in effluent in the large-scale experiment, which is lower than the maximum concentration level of Standard for drinking water quality (GB5749-2006)(0.1 mg/L).From the range analysis of orthogonal test, the order of importance of different parameters is shown as follows:pH>cooperation time>the dosage of biologics>temperature>dosage of PAM>hydrolysis time.The sludge properties were analyzed by SEM, EDS,XRD and IR. The results showed that the surface morphology of manganese-containing sludge was amorphous and rod and the main phase was CaSO4.The proportion of manganese in the sludge reached up to 14.16%, indicating that the sludge could be reused for manganese recovery. In the hydrolyzation process, manganese ions was complexed with the functional groups including-OH,-COOH,-NH,-C=O,-SO3,-CO (H) and C-Cl in biologics, and then formed precipitation.The optimum condition of the treatment of manganese-containing wastewater by biologics in pilot scale was 0.6 of mass ratio of biologics to manganese,40 min of cooperation time,60 min of hydrolysis time, 25℃of temperature, pH 10.0.Under the above optimum condition, manganese concentration decreased from 333 mg/L to 0.05 mg/L, which is lower than the maximum concentration level of Standard for drinking water quality (GB5749-2006) (0.1 mg/L). Processing cost is proportional to the manganese ion concentration in the wastewater. As the average concentrations of manganese ion in the wastewater of Xiangtan electrochemical technology Co.,LTD are blew 600 mg/L, the cost of biologics reagent is below 3.00 RMB/m3.更多还原