TiO_(2)/改性煤矸石复合光催化材料的制备及其去除水体中苯酚

以固废物煤矸石(CG)为载体,以Ti(SO_(4))_(2)为钛源,采用水热法制备煤矸石负载型二氧化钛(TiO_(2)/CG)用于含酚废水的处理。利用X射线衍射(XRD)、扫描电镜(SEM)、红外光谱(FT-IR)对产物的组成和微观形貌结构进行表征。以苯酚为目标污染物,考察TiO_(2)/CG/St的投加量、苯酚溶液初始浓度和反应温度对苯酚去除率的影响,研究反应动力学规律。结果表明,TiO_(2)以锐钛矿的形式被成功负载于煤矸石表面后可有效提高其光催化性能。当TiO_(2)/CG用量为2 g/L、反应时间为60 min、反应温度为20℃、苯酚初始浓度为100 mg/L、苯酚初始pH值为5,苯酚去除率达到59%。去除苯酚过程符合伪二级动力学模型。

煤矸石负载TiO_(2)复合高分子材料的制备及其去除水体中苯酚的研究

以固废物煤矸石(CG)为载体,以Ti(SO_(4))_(2)为钛源,采用水热法制备煤矸石负载型二氧化钛(TiO_(2)/CG),并通过淀粉(St)对TiO_(2)/CG进行表面改性,得到TiO_(2)/St/CGTiO_(2)/St/CG复合高分子材料,用于处理含酚废水。利用扫描电镜和红外光谱对产物的组成和微观形貌结构进行表征。以苯酚为目标污染物,考察TiO_(2)/St/CG投加量、苯酚初始pH、反应时间、苯酚溶液初始浓度和反应温度对苯酚去除率的影响,研究反应动力学规律。结果表明:TiO_(2)以锐钛矿的形式被负载于煤矸石表面,通过淀粉与TiO_(2)之间形成的C—O—Ti键,实现了淀粉对其表面改性。当TiO_(2)/St/CG用量为2g/L、反应时间为60min、反应温度为30^(o)C、苯酚初始浓度为20mg/L、苯酚初始pH为5,苯酚去除率达到64%。伪二级动力学模型拟合相关系数在0.99以上,能很好地描述苯酚在材料上的吸附行为。

The Kinetics for Electrochemical Removal of Ammonia in Coking Wastewater

Electrochemical removal of ammonia is a new and effective method in coking wastewater.The reaction mechanism of ammonia removal was proved by stable polarization curve in this paper.First,the supposing of reaction steps of the electrode were proposed.And then reaction parameter of the electrode was measured by Tafel curve.Finally,the reaction mechanism was determined by quasi-equilibrium approach.The results showed that Cl2+H2O→HOCl+H++Cl was the rate-determining step,the calculated apparent transfer coefficient was uniform to the experimental value.

Generation and transformation of ROS on g-C_3N_4 for efficient photocatalytic NO removal:A combined in situ DRIFTS and DFT investigation

Understanding the performance of reactive oxygen species(ROS)in photocatalysis is pivotal for advancing their application in environmental remediation.However,techniques for investigating the generation and transformation mechanism of ROS have been largely overlooked.In this study,considering g‐C3N4 to be a model photocatalyst,we have focused on the ROS generation and transformation for efficient photocatalytic NO removal.It was found that the key to improving the photocatalysis performance was to enhance the ROS transformation from·O2^-to·OH,elevating the production of·OH.The ROS directly participate in the photocatalytic NO removal and tailor the rate‐determining step,which is required to overcome the high activation energy of the intermediate conversion.Using a closely combined experimental and theoretical method,this work provides a new protocol to investigate the ROS behavior on g‐C3N4 for effective NO removal and clarifies the reaction mechanism at the atomic level,which enriches the understanding of ROS in photocatalytic environmental remediation.

Theoretical evaluation on nitrogen removal of step-feed anoxic/oxic activated sludge process

Evaluation on nitrogen removal of step-feed anoxic/oxic activated sludge process at the standpoint of reaction kinetics and process kinetics was conducted. Theoretical biological nitrogen removal efficiency was deduced based on the mass balance of nitrate in the last stage. The comparison of pre-denitrification process and step feed process in the aspects of nitrogen removal efficiency, volume of reactor and building investment was studied, and the results indicated that step-feed anoxic/oxic activated sludge process was superior to pre-denitrification process in these aspects.

Degradation of Nitrobenzene-Containing Wastewater with O_3 and H_2O_2 by High Gravity Technology

Nitrobenzene-containing industrial wastewater was degraded in the presence of ozone coupled with H2O2 by high gravity technology. The effect of high gravity factor, H2O2 concentration, pH value, liquid flow-rate, and reaction time on the efficiency for removal of nitrobenzene was investigated. The experimental results show that the high gravity technology enhances the ozone utilization efficiency with O3/H202 showing synergistic effect. The degradation efficiency in terms of the COD removal rate and nitrobenzene removal rate reached 45.8% and 50.4%, respectively, under the following reaction conditions, viz.： a high gravity factor of 66.54, a pH value of 9, a H2O2/O3 molar ratio of 1：1, a liquid flow rate of 140 L/h, an ozone concentration of 40 rag/L, a H2O2 multiple dosing mode of 6 mL/h, and a reaction time of 4 h. Compared with the performance of conventional stirred aeration mixers, the high gravity technology could increase the COD and nitrobenzene removal rate related with the nitrobenzene-containing wastewater by 22.9% and 23.3%, respectively.

Removal of Di-n-butyl Phthalate Using Immobilized Microbial Cells

The biodegradation of di-n-butyl phthalate （DBP） using immobilized microbial cells was carded out in an internal airlift loop reactor with ceramic honeycomb supports. A strain that is capable of degrading DBP was isolated from the activated sludge and identified as Bacillus sp. using 16S rDNA sequential analysis. Bacillus sp. could be rapidly attached onto the ceramic honeycomb supports. The immobilized cells could effectively degrade DBP in batch and continuous experiments. When the influent concentration of DBP was 50mg·L^-1, the effluent DBP reached less than lmg.L i with 6h hydraulic retention time （HRT） in continuous experiment. The immobilized microbial cells could grow and accumulate through the biodegradation of DBP, and the rate of degradation is accordingly increased. The possible pathway of DBP biodegradation using immobilized cells was tentatively proposed.

The Role of Formed Microorganism in Sludge on Processing of Wastewater Treatment

Several microorganisms such as bacteria, fungi, Protozoa, Rotifera, cystic amoeba and algae diagnosed in activated sludge aerobic （Rustumiya treatment plant） and anaerobic reactor. Results have shown a reduction in the turbidity rates when using activated sludge at Rustumiya plant of 76.3 to 2.653 NTU in pre-treatment and final tank respectively, also COD （chemical oxygen demand） amount reduced from 427.263 to 82 mg/L respectively, In addition, concentrations of phosphates and nitrates decreased from 12.083 to 8.426 mg/L and 3.59 to 2.43 mg/L respectively, by removing 30.2% and 32.3% respectively of the final tank. The ratio of ammonia removing was 89.6% for ammonia, reducing process from 1358 to 140 mg/L. Furthermore, sulfates concentration decreased from 30.883 to 23.337 mg/L. However, the system in the anaerobic reactor depends on non-aerated activated sludge. Results show turbidity reduced from 12.5 to 2 NTU in pre-treatment and final tank respectively, also the COD mount reduced from 191 to 130 mg/L, the percentage removal of 31.9%. In addition phosphates, nitrates and sulfates concentrations were decreased by using activated sludge from 17.15 to 8.15, 1.2 to 0.1 and 28 to 9.2 mg/L respectively. The ammonia concentration has reduced from 1.2 to 0. i mg/L where at a removal percentage of 90.9%.

Fluidized-Bed Bioreactor Applications for Biological Wastewater Treatment： A Review of Research and Developments

Wastewater treatment is a process that is vital to protecting both the environment and human health. At present, the most cost-effective way of treating wastewater is with biological treatment processes such as the activated sludge process, despite their long operating times. However, population increases have created a demand for more efficient means of wastewater treatment, Fluidization has been demonstrated to in- crease the efficiency of many processes in chemical and biochemical engineering, but it has not been widely used in large-scale wastewater treatment. At the University of Western Ontario, the circulating fluidized-bed bioreactor （CFBBR） was developed for treating wastewater. In this process, carrier particles develop a biofilm composed of bacteria and other microbes. The excellent mixing and mass transfer characteristics inherent to fluidization make this process very effective at treating both municipal and industrial wastewater. Studies of lab- and pilot-scale systems showed that the CFBBR can remove over 90% of the influent organic matter and 80% of the nitrogen, and produces less than one-third as much biological sludge as the activated sludge process. Due to its high efficiency, the CFBBR can also be used to treat wastewaters with high organic solid concentrations, which are more difficult to treat with conventional methods because they require longer residence times; the CFBBR can also be used to reduce the system size and footprint. In addition, it is much better at handling and recovering from dynamic loadings （i.e., varying influent volume and concentrations） than current systems. Overall, the CFBBR has been shown to be a very effective means of treating wastewa- ter, and to be capable of treating larger volumes of wastewater using a smaller reactor volume and a shorter residence time. In addition, its compact design holds potential for more geographically localized and isolat- ed wastewater treatment systems.

Experimental Research on Coke Wastewater Treatment by Hybrid Biological Reactor

Phase hybrid biological reactor （HBR） was used in treating coke wastewater by adding submerging fiber-ball fillers in suspended growth activated sludge. The optimum operation parameters for the highest performance were determined. It was found that the hybrid biological reactor worked well for the coke wastewater treatment in terms of Chemical Oxygen Demand （COD）, NH4＋ -N and other refractory organic compounds removal efficiencies. Compared with conventional activated sludge system, the removal rate of COD and NH4＋ -N and the nitrating rate were higher and more stable in the hybrid biological reactor. COD of effluent was less than 75 mg/L and the removal rate of COD and NH4＋ -N could be up to 95.0% and 92.5% when COD of influent and NH4＋ -N were less than 700 mg/L and 300 rag/L, respectively. In this way, the quality of effluent concentration could reach the first class of integrated wastewater discharge standard （GB8978-1996） （COD ≤100 mg/L）.

Removal of tin and extraction of indium from acid-dissolved solution of waste indium-tin targets

The recovery of indium from waste indium tin oxide （ITO） target has great significance for the economy and environment.Based on our previous study on the optimization of acid leaching technique,the present study focuses on tin removal via zinc substitution and indium recovery from a tin-free leach solution.The results show that when the amount of added zinc powder and reaction time increase,the tin removal effect can be improved.The optimal conditions obtained are as follows：additional content of zinc powder from 20 g/L to 25 g/L,reaction temperature of 60 ℃,and reaction time from 3 h to 4 h.Under this condition,the tin removal rate exceeds 98%,and the tin content in the tin removal solution is lower than 0.05 g/L.After tin removal,the substitution time could be reduced from 3-5 d to 1-2 d by neutralizing the residual acid by using alkaline residue and maintaining the pH value less than 2.The indium recovery rate is also improved when this condition is used.The indium content in the tin residue is reduced to lower than 0.1% and the acid-insoluble β-SnO2 could be obtained via the strong nitric acid leaching of the indium-containing tin residue.Indium could be recovered from ITO with a high purity of 99.995% via electrorefining.

Study on the Effect of the Fe^2＋/NaClO Oxidation of CN

The effects of various parameters on the removal rate of CN were discussed in the paper. The results showed that under the conditions of 30℃ pH = 3.0, Fe2＋ dosage was 80 mg/L, the NaCIO concentration of 0.10 mol/L, reaction time in 60 min, Fe2＋ has a satisfactory catalytic activation, and the removal rate of CN was about 37.89%.

Experimental study on removing NO from flue gas using microwave irradiation over activated carbon carried catalyst

Nitrogen oxides(NOx) from flue gas can be removed efficiently by activated carbon continuously irradiated by microwave,which,however,needs high temperature and consumes excessive carbon. If catalyst is added into activated carbon,then reaction temperature can be reduced and selectivity of reaction enhanced. The effects on flue gas denitrification by adding different catalysts to microwave reactor were studied in this paper. It was found that the addition of catalyst could reduce the microwave power required by the same removal efficiency obviously;the difference of removal efficiency was different due to different catalysts,and the Cu-based catalyst has more catalytic action efficiency. Reaction temperature decreased by about 200℃ and removal efficiency increased by 25% after adding Cu-based catalyst. In addition,characteristic analysis for activated carbon conducted by X-ray diffraction confirmed that active component of catalyst existed on the surface of activated carbon.