UASB反应器处理PTA废水的研究

采用UASB反应器，对两种不同方法驯化的污泥处理PTA废水进行了研究，结果表明，经对苯二甲(TA)酸驯化的厌氧污泥能够稳定地处理PTA废水，在水力停留时间29～32h、进水CODcr4600-7000mg／L、废水中对TA含量1800～2080mg／L条件下，CODcr的去除率稳定在80％以上，对TA去除率稳定在70％以上；而用PTA废水驯化的污泥在同样的条件下对CODcr，去除率在61％以下，对TA去除率在40％以下。经TA驯化的污泥，其物理、生物性状比PTA废水驯化的污泥有显著提高和改善。     

广东沼气农业模式的典型调查与思考

回顾了广东沼气发展历程,介绍了广东典型沼气农业模式,包括广东西南部丘陵区典型农户沼气模式,广东东部丘陵区典型农户沼气模式,广东东北部丘陵山区典型农户沼气模式,广东低洼地和积水区农户沼气模式,以及广东规模化养殖场沼气模式,并在此基础上分析了沼气农业模式的空间分布规律、沼气模式和经济发展的关系以及沼气发展的系统工程。     

溶液浓差能驱动的逆电渗析有机废水氧化降解机理研究

将逆电渗析(RED)电极氧化还原反应作用于有机废水降解,可以达到利用低品位热氧化降解有机废水的目的.RED反应器阳极产生氧化反应生成的HClO及阳极表面直接电化学氧化反应对有机废水产生氧化降解作用,阴极发生电芬顿反应生成H_2O_2对有机废水产生氧化降解作用.为了验证溶液浓差能驱动的RED有机废水氧化降解工作机理,通过搭建一个由40对膜电池单元所构成的实验室规模的RED有机废水氧化降解反应器及相应的实验系统,对偶氮染料——酸性橙Ⅱ模拟废水进行氧化降解机理研究.通过3次重复性实验研究发现:在通过正交试验确定的最佳降解条件下,浓度为150 mg·L~(-1)各500 mL的酸性橙Ⅱ模拟废水分别流经RED反应器阴、阳两极,阴、阳极12 min酸性橙Ⅱ平均降解率分别可达90.14%和97.87%,20 min酸性橙Ⅱ平均降解率分别达到97.56%和99.81%.初步研究结果表明,溶液浓差能驱动的RED反应器对难生化降解有机物有较好的降解效果,为后续相关理论和实验研究提供了参考依据.     

逆电渗析反应器降解模拟甲基橙染料废水实验

利用逆电渗析（RED）技术可实现"废热治理废水"的目的.为探究RED反应器对染料废水的降解效果,构建了由40对膜构成的RED反应器.以NaCl水溶液作为工作溶液,甲基橙模拟废水作为降解对象,考察了废水流率、Cl^-浓度、Fe²⁺浓度、pH值、曝气流率和输出电流对模拟废水脱色率及COD去除率的影响.结果表明,对于RED反应器阳极回路印染废水,废水流率对其脱色率影响不大,但Cl^-浓度对其脱色率和COD去除率影响较大.对于RED反应器阴极回路印染废水,废水流率、Fe²⁺浓度、pH值和曝气流率均对其脱色率和COD去除率产生影响.当阳极回路废水氯盐浓度为0.5 mol·L^-1,阴极回路废水pH=2、Fe²⁺浓度为0.1 mmol·L^-1、曝气流率为600 mL·min^-1,两回路模拟废水流率均为82 mL·min^-1实验条件下,输出电流为0.25 A时,处理20 min后,阳/阴极回路模拟废水脱色率分别为99.9%和91.71%;处理80 min后,阳/阴极回路模拟废水COD去除率分别可达到52%和62%.     

PS-TMT树脂的合成及其对水溶液中Hg(Ⅱ)的吸附性能

以氯甲基聚苯乙烯树脂为载体与三聚硫氰酸反应,合成了功能化的螯合树脂PS-TMT,并对其进行了元素分析、红外光谱以及比表面表征。通过静态吸附实验研究了其对水溶液中Hg(Ⅱ)的吸附性能,结果表明,PS-TMT螯合树脂在pH值1～7范围内对Hg(Ⅱ)具有良好的吸附能力,在25℃、pH 7条件下对Hg(Ⅱ)的最大吸附容量为344 mg/g;动力学研究显示树脂对Hg(Ⅱ)的吸附在240 min内可达到吸附平衡,吸附动力学过程符合准二级动力学模型;吸附等温线则符合Langmuir吸附等温线模型。     

Comparison of diffusive gradients in thin film technique with traditional methods for evaluation of zinc bioavailability in soils

The technique of diffusive gradients in thin film (DGT) has been shown to be a promising tool to assess zinc (Zn) bioavailability in soils, but there exists considerable debate on its suitability. In this study, Zn bioavailability was systematically investigated in wheat- and maize-grown soils using this technique and seven traditional methods, including soil solution concentration and six widely used single-step extraction methods (HAc, EDTA, NaAc, NH₄Ac, CaCl₂, and MgCl₂). The concentrations of Zn in the shoots and roots of these two plant species increased continuously with increasing additions of Zn to the soils, accompanied by significant decreases in shoot biomass and root biomass at Zn concentrations greater than 400 mg kg^?1 for maize and 800 mg kg^?1 for wheat. Zinc uptake and accumulation was higher in maize roots than in wheat roots. Both the concentrations of bioavailable Zn measured by DGT (C _DGT) and soil solutions (C _sol) increased linearly with increasing additions of Zn to the soils, while no strong linear relationships were observed for the extraction methods. Higher concentrations of extractable Zn, lower values of C _sol, and larger values of R (i.e., the ratio of C _DGT to C _sol) were observed in maize-grown soils compared with those of wheat-grown soils, while the values of C _DGT between the two plants were similar. These findings demonstrate that there likely exists a stronger resupply of Zn from the soil solid phases in maize-grown soils to satisfy a higher Zn uptake and accumulation in this plant. Linear correlation analyses showed that C _DGT had the highest correlation coefficients with plant Zn concentrations compared with other traditional methods, implying that the DGT technique is more sensitive and robust in reflecting Zn bioavailability in soils to plants.     

Kinetics and equilibrium adsorption study of lead(II) onto the low cost adsorbent—Eupatorium adenophorum spreng

Adsorption of Pb(II) ions from aqueous solution onto a low cost adsorbent—the Eupatorium adenophorum spreng has been investigated to evaluate the effects of initial lead ion concentration, contact time, pH and temperature on the removal of Pb(II) systematically. The optimal pH value for Pb(II) adsorption onto the E. adenophorum spreng was found to be 5.0. Thermodynamic parameters such as standard Gibbs free energy (ΔG°), standard enthalpy (ΔH°), and standard entropy (ΔS°) were evaluated by applying the van’t Hoff equation, which describes the dependence of equilibrium constant on temperature. The thermodynamics of Pb(II) adsorption onto the E. adenophorum spreng indicated that the adsorption was spontaneous and endothermic. Langmuir and Freundlich isotherms were used to analyze the equilibrium data at different temperatures and the equilibrium data were found to fit Freundlich isotherm equation better than Langmuir isotherm. The adsorption was analyzed using pseudo-second-order kinetic models.     

Investigation of potential interferences on the measurement of dissolved reactive phosphate using zirconium oxide-based DGT technique

A diffusive gradients in thin films (DGT) technique based on hydrous zirconium oxide (Zr-oxide) has been recently developed for the measurement of dissolved reactive phosphate (DRP). In this study, the detailed performance of the DGT technique is reported. Spiking experiments revealed that several orthophosphate monoester compounds contributed to the Zr-oxide DGT measurements of DRP. However, such a phenomenon is unlikely to occur during field conditions due to the low concentration of organic P in typical natural waters. The presence of Cl- (up to 106 g/L), SO42- (up to 16 g/L), HCO3- (up to 817 g/L), and AsO2- and AsO 3 4 (both up to 1 mg As/L) in solutions had negligible effects on the measurement of DRP. The threshold concentrations of Cl-, SO42- and HCO3- have been increased from previous reports for the measurements of DRP using other adsorbent-based DGT techniques. The capacity for DGT measurements of DRP decreased with increasing solution pH (4.2-9.2). The lowest capacity (95 μg P/m2 at pH 9.2) was still greater than that of other DGT techniques that are usually used for the measurement of DRP (2-12 μg P/cm2 ). The Zr-oxide binding gel could be stored for up to 2 years without any aging effect. This period of validity was considerably longer than the ferrihydrite binding gel that is commonly used in present DGT devices (6 months). The field application revealed that the concentrations of DRP measured in three fresh water samples using the Zr-oxide DGT technique were in agreement with those of the traditional colorimetric method.     

脱水污泥/松木锯末水蒸气共气化研究

以城市污水处理厂机械脱水后的污泥(含水率约为80％)和松木锯末的混合物为原料,进行了共气化制取富氢燃气的研究.同时,采用热重分析(TGA)研究了混合样品的热失重特性,并在固定床反应器上考察了不同掺混比对燃气成分、燃气产量和碳转化率的影响.TGA结果表明,随着锯末掺混比的增加,样品的失重量、最大失重率及挥发分析出特性指数增大.在固定床反应器中,脱水污泥中的水分在高温条件下形成蒸气气氛,与产生的半焦发生了蒸气气化反应.实验结果表明,最佳掺混比为40％ ～ 60％,此时氢气含量、燃气产量、碳转化率分别为40％、0.70 m3· kg-1、64.1％.此外,借助BET和SEM对残余半焦的比表面积及表面形貌特征进行了分析.     

Seasonal variation characteristics of hydroxyl radical pollution and its potential formation mechanism during the daytime in Lanzhou

Hydroxyl free radicals (OH radicals) play the main role in atmospheric chemistry and their involving reactions are the dominant rate determining step in the formation of secondary fine particulate matter and in the removal of air pollutants from the atmosphere. In this paper, we studied the seasonal variation characteristics of OH radicals during the daytime in Lanzhou and explored the potential formation mechanism of high concentration OH radicals. We found that the OH radicals in four seasons was 2.7 × 10⁶, 2.6 × 10⁶, 3.1 × 10⁶, and 2.2 × 10⁶ cm^?3, respectively. Since the rainfall was concentrated in summer, the wet deposition had a significant effect on removing OH radicals. Among the four pollutants (including ozone (O₃), volatile organic compounds (VOCs), nitrogen dioxide (NO₂) and fine particulate matter (PM_2.5)), the variation of OH radicals were closely related to ozone concentration especially in spring and summer. In autumn, the correlation between PM_2.5 and OH radicals were the closest among the observing pollutants and its formation mechanism was different conventional regeneration pathway. In Event 1, high concentration of ozone was the main source of OH radicals; under the high humidity condition, except for ozone, the multiple factors including VOCs, NO₂ and PM_2.5 interplayed and leaded to the Event 2.