微污染水中苯酚光催化降解的健康风险评价

利用微污染水中苯酚光催化降解的试验统计结果进行了环境健康风险评价.结果表明,在苯酚初始浓度为0.004～0.05 mg/L的试验条件下,反应30～85 min时,苯酚含量降至0.002mg/L的安全标准值(健康危害风险为8.16×10-12a-1),但中间产物邻苯二酚、对苯二酚的最大健康危害风险分别高达2.45×10-11a-1和2.04×10-11a-1,且风险度随苯酚初始浓度的增大而增强.说明利用光催化降解微污染水中苯酚的健康安全初始浓度小于0.01 mg/L,安全反应时间大于85 min.     

水上介质阻挡放电等离子体去除微囊藻毒素-LR的研究

研究水上介质阻挡放电等离子体对微囊藻毒素-LR(MC-LR)的去除及其反应动力学。在室温和常压下,考察了峰值电压、初始电导率、溶液初始浓度和pH对降解率影响。结果表明,水上介质阻挡放电等离子体降解MC-LR的过程均符合一级反应动力学。随着峰值电压的升高,MC-LR的降解率升高。高的溶液初始电导率和初始浓度不利于放电等离子体MC-LR的去除,反应过程中溶液的电导率增长速率与毒素降解速率呈现正相关性;pH在酸性和碱性条件下更有利于毒素的去除,反应20min后溶液pH均会下降到3左右,H+浓度直线上升;初始浓度为26.16μg/L的MC-LR经过100min的处理之后降解到0.23μg/L,去除率达到99.35%,低于国家《生活饮用水卫生标准》(GB5749～2006)限值1μg/L。     

活性炭吸附法脱除地热水中微量苯酚的试验研究

研究了精制椰壳活性炭吸附地热水中微量苯酚的各项参数,通过静态试验系统考察了活性炭用量,水样pH,反应时间,苯酚初始浓度等重要因素,确定了处理地热水中苯酚的最佳条件:活性炭用量6 g/L,pH值6.5,反应时间6 h,苯酚的初始浓度0.5 mg/L,处理效果最佳;并据此进行了动态小试试验,从动力学角度分析吸附原理,其动力学更好的符合伪二级反应动力学模型。将动态试验数据在origin软件中处理,得到适用于活性炭固定床吸附苯酚的穿透曲线模型,旨在为苯酚吸附过程的设计提供参考。     

Fe掺杂A-TiO_2在溴甲酚绿中的可见光催化活性及动力学

以FeCl_3·6H_2O为Fe源,采用水热法制备了Fe掺杂锐钛型TiO_2(A-Ti O2)光催化剂。以溴甲酚绿为降解对象,考察溴甲酚绿的初始浓度、催化剂用量、掺Fe量等因素对自制催化剂可见光催化降解反应的动力学方程的影响。结果表明:在40 W白炽灯照射下,当溴甲酚绿初始浓度为10 mg/L(pH=7)、催化剂的用量为0.6 g/L、掺Fe量为4%(摩尔分数)、室温下反应时间为3 h时,溴甲酚绿的降解率最大为76.05%。溴甲酚绿光催化降解曲线符合一级反应动力学方程,于上述最佳条件下其表观反应速率常数k达到最大值,为0.389 7 h-1。     

UV和UV/H_2O_2光解饮用水中六六六效果的研究

采用UV、UV/H2O2两种工艺分别光氧化降解饮用水中低浓度持久性有机氯农药benzene hexachloride(BHC),试验研究了不同初始浓度的α-BHC和H2O2、不同光照强度及pH对α-BHC去除效果的影响。结果表明光降解过程符合一级反应动力学模型;α-BHC的光降解速率常数随着初始浓度、光强、pH的增加而增加。一定浓度范围的H2O2有助于α-BHC的光降解,但过高反而抑制其反应速率。UV/H2O2联用对α-BHC的去除具有协同作用。     

含沙量对水体耗氧有机污染物降解耗氧影响

在泥沙存在情况下,水体中的耗氧有机污染物的降解耗氧规律与清水中有很大的差异。从水体耗氧有机物降解反应动力学和溶解氧反应动力学方程出发,考虑泥沙对耗氧有机污染物降解的影响,得出了耗氧有机物降解过程耗氧量随时间变化表达式。通过室内实验研究了含沙量对耗氧有机污染物的耗氧规律的影响,利用耗氧量随时间表达式对实验数据进行分析,得出了泥沙影响下的耗氧有机污染物耗氧速率常数与含沙量的一般规律。结果表明,泥沙对耗氧有机污染物降解耗氧过程符合一级动力学反应,且耗氧速率常数随含沙量的增大而增大,由泥沙存在引起的溶解氧衰减速率常数与含沙量之间存在非线线的函数关系。     

镉对污水生物脱氮反应动力学的影响研究

通过批量试验检测COD、NH+4-N和NOx-N的去除率和比降解速率,研究了Cd2+对活性污泥生物脱氮反应动力学的影响。结果表明:在硝化反应和反硝化反应有机物降解过程中,5 mg/L的Cd2+即会对有机物的去除率产生抑制作用,20 mg/L的Cd2+对有机物去除率和有机物比降解速率有显著抑制效应;在硝化反应NH+4-N的去除过程中,20mg/L的Cd2+会显著抑制对NH+4-N的去除,10 mg/L的Cd2+可造成比硝化速率的显著降低;在反硝化反应NOx-N的去除过程中,Cd2+对NOx-N去除率没有显著影响,20 mg/L的Cd2+对比反硝化速率有显著抑制效应。     

二维电极电解法去除水中硝酸盐试验研究

目前硝酸盐污染已经严重影响了地下水水质,对饮用水安全构成了一定威胁。本研究拟采用电化学方法去除水体中硝酸盐,探究其机理、动力学、影响因素及实际地下水处理方法,为地下水脱氮提供参考。研究结果表明:在无氯离子体系下,30.0 mg/L的硝酸盐在2.0 A电流下电解,其一级反应动力学常数为0.040 h-1,产物中54%为氨氮,46%为氮气。在添加300.0 mg/L氯离子条件下电解,一级反应动力学常数为0.029 h-1,其产物主要为氮气。硝酸盐去除速率随着硝酸盐初始浓度和电流增加而增加,随着氯离子浓度增加而略微减少。对实际地下水水样的电解结果表明,20.0 mg/L的硝酸盐在2.0 A、100.0 mg/L氯离子条件下电解,其一级反应动力学常数为0.031 h-1,产物主要为氮气。二维电极电解过程中,硝酸盐扩散至阴极表面速率较慢,电解效率较低。     

城市污泥中DEHP和DMP的好氧降解特性研究

对城市污泥好氧消化过程中DEHP和DMP的降解进行了研究,并重点研究了难降解有机物DEHP在不同浓度下对易降解有机物DMP的抑制效果.研究表明,好氧消化污泥对DEHP和DMP有较强的降解能力,且对DMP的降解能力明显强于DEHP,好氧消化污泥在500 mg/L难降解有机物DEHP存在的情况下,对50 mg/L有机物DMP的去除率仍高达99.8%;当DEHP的初始浓度在200 mg/L时,对DMP的降解速率影响较大,而在50 mg/L和500 mg/L时,影响较小;但历经10 d以后,不同初始浓度的DEHP对DMP的好氧降解速率几乎没有影响.     

对硝基苯酚起声降解反应动力学方程的建立

在对硝基苯酚初始浓度、溶液初始pH、声能密度、反应温度及曝气等对超声降解对硝基苯酚溶液效果的影响及规律的基础上,通过研究超声降解对硝基苯酚模拟废水,建立了对硝基苯酚超声降解反应动力学方程.该动力学方程对于研究超声降解对硝基苯酚的反应具有很好的指导意义.     

Biodegradation of 2-chlorophenol (2CP) in an anaerobic sequencing batch reactor (ASBR)

The aim of this study is to contribute to the knowledge about anaerobic digestion of 2-chlorophenol (2CP) in an anaerobic sequencing batch reactor (ASBR). Two reactors were set up (ASBR(A) and ASBR(B)). The ASBR(A) was fed with 2-chlorophenol (28-196 mg 2CP-C/L) and no other exogenous electron donor. The ASBR(B) was fed with a mixture of 2CP (28-196 mg 2CP-C/L) and phenol (28-196 mg phenol-C/L) as an electron donor. The process evaluation was conducted by three means: first by substrate consumption efficiency (E(2CP)), second, by biogas yield (Y(biogas-C/2CP-C)) and third, by the specific consumption rates (q(2CP)) as response variables. The 2CP consumption efficiency (90 ± 0.4%) was not influenced by the increase in the concentrations tested. In both reactors ASBR(A) and ASBR(B), both concentration as well as speed increased. Concentration increased from 28 to 114 mg 2CP-C/L. The specific consumption rate (q(2CP)) values were fivefold higher. However, a decrease of 37% was observed at 140 mg 2CP-C/L and one of 72% at 196 mg 2CP-C/L. The biogas yields (0.80 ± 0.06) remained stable in both reactors. In both reactors the biogas yield decreased to 78 ± 3% at 196 mg 2CP-C/L. We might assume this decrease was due to the accumulation of VFA. Finally, poor sludge settleability was determined only in the SBR(B) reactor at 140 and 196 mg 2CP-C/L. An increase was observed in both SVI ≤ 140 ± 5 mL/g and over exopolymeric protein ≤120 mg EP/L.     

负载型纳米TiO2光催化降解罗丹明B动力学与机理研究

采用负载型纳米TiO2/AC在流化床反应器中降解罗丹明B染料废水。研究了罗丹明B的光催化降解反应动力学与降解机理。结果表明,负载型纳米TiO2光催化降解罗丹明B过程符合一级动力学方程,降解机理首先是罗丹明B分子发色基团苯氨基、羰基键被破坏,然后是无色中间产物的逐渐降解。     

Co-degradation of phenol and m-cresols by upflow anaerobic sludge blanket reactor.

The study was performed to assess the efficacy of an upflow anaerobic sludge blanket reactor for the degradation of mixtures of phenol and m-cresol. The experiments were performed in an upflow anaerobic sludge blanket reactor. The reactor was seeded with digested sewage sludge and was initially operated at 24 HRT. A phenol concentration of 200 mg/L was fed to the reactor to acclimatize the microorganisms to phenols. Subsequently the dosages of phenols were increased to 400 mg/L, 500 mg/L, and 600 mg/L. Cresols were introduced in the reactor when phenol removal efficiency of 77% was achieved at phenol concentration of 600 mg/L. Different phenol to m-cresol ratios were tried and the performance of the reactor was evaluated for each case. The result demonstrates that it is important to consider phenol/ m-cresol ratio to avoid toxic effects and both can be co-degraded successfully under anaerobic conditions provided proper acclimatization time is given.     

Performance comparison of a continuous-flow stirred-tank reactor and an anaerobic sequencing batch reactor for fermentative hydrogen production depending on substrate concentration.

This study was conducted to compare the performance of a continuous-flow stirred-tank reactor (CSTR) and an anaerobic sequencing batch reactor (ASBR) for fermentative hydrogen production at various substrate concentrations. Heat-treated anaerobic sludge was utilized as an inoculum, and hydraulic retention time (HRT) for each reactor was maintained at 12 h. At the influent sucrose concentration of 5 g COD/L, start-up was not successful in both reactors. The CSTR, which was started-up at 10 g COD/L, showed stable hydrogen production at the influent sucrose concentrations of 10-60 g COD/L during 203 days. Hydrogen production was dependent on substrate concentration, resulting in the highest performance at 30 g COD/L. At the lower substrate concentration, the hydrogen yield (based on hexose consumed) decreased with biomass reduction and changes in fermentation products. At the higher substrate concentration, substrate inhibition on biomass growth caused the decrease of carbohydrate degradation and hydrogen yield (based on hexose added). The ASBR showed higher biomass concentration and carbohydrate degradation efficiency than the CSTR, but hydrogen production in the ASBR was less effective than that in the CSTR at all the substrate concentrations.     

膨润土负载纳米零价铁去除水中铅的研究

将纳米零价铁通过液态还原法负载于膨润土上,目的是为了比较负载对提高纳米零价铁去除重金属铅的能力的影响。从负载后扫描电镜图像中可以看出,负载后的纳米零价铁分散度更好。在相同投加量下,负载了纳米零价铁的膨润土对重金属铅的去除能力要远高于膨润土和纳米零价铁。铅的起始浓度为200mg／L,膨润土＋纳米零价铁的复合材料在0．4g／L的投加量下,去除率就达到90％以上。对材料的动力学研究结果则表明：纳米零价铁的反应速度较快,大部分的铅的去除都在1h以内完成。将吸附动力学实验结果进行一级和二级动力学反应拟合。二级拟和的线性相关系数明显高于一级。说明纳米零价铁和膨润土＋纳米零价铁复合材料与铅的反应更符合二级动力学反应假设。另外,纳米零价铁对铅的去除受到起始浓度的影响较大,而膨润土＋纳米零价铁则基本不受起始浓度的影响。     

Aerobic biodegradation of 3-chlorophenol in a sequencing batch reactor: effect of cometabolism.

The aim of the present study was to investigate how phenol modifies, through cometabolism, the biodegrading capability of 3-chlorophenol (3-CP) in a sequencing batch reactor seeded with a mixed culture obtained from a domestic sewage treatment plant. Two laboratory-scale SBRs, one fed 3-CP only and the other fed 3-CP and phenol in the same concentration, were seeded with the partially acclimated biomass. The removal capability in both reactors was measured for progressive increases in the feed organic loading. Cometabolism enhanced biodegradation of 3-CP by reducing both the initial lag period and the time required for the complete removal. 700 mg/L 3-CP was demonstrated to be the highest concentration, which could be completely degraded during the active phase (fill plus react) either in the presence or absence of phenol as the growth substrate even though the lag period was shorter when phenol was present. The operating strategy required modification for the complete removal of 800 mg/L 3-CP. An increase in the phenol to 3-CP ratio did, however, improve 3-CP degradation rate.     

水解酸化-好氧移动床膜生物反应器处理高浓度有机废水的试验研究

好氧移动床膜生物反应器(M-CMCBR)是生物膜法与微滤膜相结合的一种新型反应器。采用水解酸化-好氧移动床膜生物反应器处理高浓度有机废水和含酚废水。试验结果表明:此工艺可以提高难降解有机废水的可生化性,继而得到较好的出水水质。进水CODCr为3000～5000mg/L时,最终膜出水CODCr为30～90mg/L,总去除率为98.5%～99.5%。     

Determination of reaction rate constants for phenol oxidation using SnO2/Ti anodes coupled with activated carbon adsorption in the presence of TiO2 as catalyst

Series of experiments for phenol degradation with assistance of TiO2 catalyst at pH of 6.5 and temperature of 25 degrees C were conducted using a lab-scale electrochemical reactor constructed in our laboratory. According to the results, at the presence of the TiO2 catalyst the removal of phenol was increased and first-order kinetics could describe the evolution of phenol concentration. For inspecting the relationship between rate constants and dosage of TiO2, two possible kinetics were proposed in this study. Contrasted to the abundant experimental data, a reasonable kinetics was obtained for the estimation of phenol concentration effluent during continuous flow of raw wastewater, especially when the TiO2 dosage was less than 0.5g L(-1). The model obtained from these experiments could employed for the calculation of rate constants at different TiO2 dosage and the necessary dosage of catalyst when a discharge standard was designed.     

两段ABR—A/O工艺在高浓度硫酸盐制药废水处理中的应用

在高浓度硫酸盐制药废水的厌氧处理中,硫酸盐还原菌通过竞争性与非竞争性抑制影响产甲烷菌的活性和生长率。采用两段ABR-A/O组合工艺处理含高浓度硫酸盐制药废水。结果表明:系统稳定运行后,进水CODCr为10500～15000mg/L,SO42-为1000～1500mg/L时,CODCr、SO42-去除率分别达到98%和92%,出水各项指标均达到《污水综合排放标准》(GB8978—1996)二级标准。     

Ti/MCM-22/MCM-41微介孔复合材料光催化降解酸性红B模拟废水的研究

采用纳米自组装法制备了具有吸附性和光催化性的Ti/MCM-22/MCM-41微介孔复合材料,利用X射线衍射、N2吸附、扫描电镜等方法对其进行表征。将复合材料用于光催化降解酸性红B的实验,考察了催化剂用量、光照时间、pH值和染料初始浓度对光催化降解率的影响,并对光降解产物进行了紫外光谱分析。结果表明:当染料的初始浓度为50 mg/L,废水pH在6左右,催化剂投加量为0.1 g/L,光照时间120 min,酸性红B的去除率可达98%以上,光催化降解反应遵循一级反应动力学方程。降解产物的紫外光谱图表明,降解后酸性红B的两个特征吸收带消失,结构的共轭系被打破,颜色消失,说明该复合材料去除水中的酸性红B主要是通过光催化作用。