Experimental study and kinetic analysis of oxidant-free thermal-assisted UV digestion utilizing supported nano-TiO2 photocatalyst for detection of total phosphorous

A novel thermal-assisted ultra-violet (UV) photocatalysis digestion method for the determination of total phos-phorus (TP) in water samples was introduced in this work. The photocatalytic experiments f...     

Desulfurization of gasoline by condensation of thiophenes with formaldehyde in a biphasic system using aqueous phase of acids

Aqueous phase of acids as catalysts for the desulfurization of gasoline by condensation of thiophenes with formaldehyde in a biphasic system was investigated. Two types of model gasoline with and without aromatics and olefins were employed in this work. The desulfurization rates were above 90% on these two types of model gasoline using formic acid and H_3PW_(12)O_(40)(0.8 mol·L~(-1)), indicating that the presence of aromatics and olefins has no effect on the desulfurization rate. High temperature(above 90 °C) was more favorable to the process for desulfurization. Four hours was considered to be the proper treating time for the sulfur removal. In addition,aqueous phase of acids could be recycled at least 4 times without decreasing desulfurization rate. Finally, the possible process for the integration of condensation desulfurization into the existing refinery process for the production of gasoline with low sulfur content was proposed.     

UV enhanced gas-solid synthesis of chlorinated poly vinyl chloride characterized by a UV-Vis online analysis method☆

Dynamic characteristics of UV enhanced gas–solid PVC chlorination process were revealed by a UV–Vis spectral online analysis method. Experimental results showed an instantaneous increase of the chlorination rate as soon as UV lightwas affiliated, which demonstrated the intensified effect of UV radiation on PVC chlorination directly. Different affiliationmethods of UV light were then studied, proving that continuous UV radiation could enhance the chlorination process significantly while intermittent UV radiation was able to initiate the chlorination reaction once it was conducted. Besides, experiments were carried out to study the influences of parameters on the chlorination process such as UV wavelength, chlorination temperature, partial pressure of chlorine gas and PVC raw materials. Among all the parameters, chlorination temperature and partial pressure of chlorine gas were testified as two key factors to determine the chlorination performance. Thermal analysis of CPVC products showed that their corresponding properties such as the glass transition temperature (T_g) and the homogeneity of chlorine distribution in polymer phase were improved with the increase of chlorine content.     

Effect of endogenous hydrogen utilization on improved methane production in an integrated microbial electrolysis cell and anaerobic digestion: Employing catalyzed stainless steel mesh cathode

Improving the production of methane,while maintaining a significant level of process stability,is the main challenge in the anaerobic digestion process.Recently,microbial electrolysis cell (MEC) has become a promising method for CO2 reduction produced during anaerobic digestion (AD) and leads to minimize the cost of biogas upgrading technology.In this study,the MEC-AD coupled reactor was used to generate and utilize the endogenous hydrogen by employing biocompatible electrodeposited cobalt-phosphate as catalysts to improve the performance of stainless steel mesh and carbon cloth electrodes.In addition,the modified version of ADM1 model (ADM1da) was used to simulate the process.The result indicated that the MEC-AD coupled reactor can improve the CH4 yield and production rate significantly.The CH4 yield was enhanced with an average of 48％ higher than the control.The CH4 production rate was also increased 1.65 times due to the utilization of endogenous hydrogen.The specific yield,flow rate,content of CH4,and pH value were the variables that the model was best at predicting (with indexes of agreement:0.960/0.941,0.682/0.696,0.881/0.865,and 0.764/0.743) of the process with SS-meshes 80/SS-meshes 200,respectively.Employing the catalyzed SS mesh cathode,in the MEC-AD coupled reactor,could be an effective approach to generate and facilitate the utilization of endogenous hydrogen in anaerobic digestion of CH4 production technology,which is a promising and feasible method to scale up to the industrial level.     

A safe and efficient process for the preparation of difluoromethane in continuous flow

Difluoromethane is typically produced vialiquid-phase fluorination as performed in a batch reactor. However,this process suffers from some problems, e.g., severe corrosion of the reactor, high safety risk, and the regeneration of the catalyst. In this paper, a flow process as performed in the tubular reactor was designed. The optimum conditions for continuous synthesis of difluoromethane were obtained as follows: the reaction temperature was 100℃, the molar ratio of dichloromethane to hydrogen fluoride was 1.6:1 and the reaction time was 300 s. The operation of the cyclic process was stable for 24 h with the conversion per pass of hydrogen fluoride up to 16.2%.The unreacted raw materials were easily reused. The deactivation of the common catalyst, antimony pentachloride, was investigated by catalyst concentration curve and XPS analysis. The approach proposed in this work is proven to be safe, efficient and low amount of catalyst.     

喷雾干燥法制备载药微球时的形貌与粒度控制

Drug-loaded microspheres are usually used as a biophysically targeted delivery system. The morphology and size distribution of the microspheres are key effects on the efficiency in therapy. The microspheres could be prepared by the spray drying method, and the characterization could be controlled by varying the drying conditions. The whole preparation process is highly efficient, and suitable for commercialization. In this work, a case for preparation of the microspheres of tanshinone (TAN) solid dispersions was studied, and the mechanisms of morphology and size control of microspheres during the spray drying process were investigated. The effects of inlet temperature, concentration and components of precursors, and feed rate on the morphology and size distribution of products were studied. The results showed that the morphology of the dry products depended on the inlet temperature, the components of precursor and feed rate. Among them, temperature was the most important factor. The size of microspheres was mainly controlled by the concentration of the precursor. This work might be a reference for morphology and size control of targeted drug delivery microspheres by the spray drying method.     

天然气管网吸附调峰可行性的模拟研究

A lo9adleveling method through adsorption was presented to adjust the supply quantity according to the consumption rate of natural gas with time,An experimental simulation set up was designed and used to test the load-leveling function for a real pipline system.A storage tank filled with activated carbon together with a filter constitutes the major part of the load-leveling facility,Pressure and temperature of the system,as well as the real gas output of the storage tank were recorded.It is proven that load-leveling by adsorption in technically feasible even for low pipeline pressure of natural gas supply system.     

流化床反应器中气相丙烯聚合反应的动力学和预测控制(英文)

A two-phase dynamic model, describing gas phase propylene polymerization in a fluidized bed reactor, was used to explore the dynamic behavior and process control of the polypropylene production rate and reactor temperature. The open loop analysis revealed the nonlinear behavior of the polypropylene fluidized bed reactor, jus- tifying the use of an advanced control algorithm for efficient control of the process variables. In this case, a central- ized model predictive control （MPC） technique was implemented to control the polypropylene production rate and reactor temperature by manipulating the catalyst feed rate and cooling water flow rate respectively. The corre- sponding MPC controller was able to track changes in the setpoint smoothly for the reactor temperature and pro- duction rate while the setpoint tracking of the conventional proportional-integral （PI） controller was oscillatory with overshoots and obvious interaction between the reactor temperature and production rate loops. The MPC was able to produce controller moves which not only were well within the specified input constraints for both control vari- ables, but also non-aggressive and sufficiently smooth for practical implementations. Furthermore, the closed loop dynamic simulations indicated that the speed of rejecting the process disturbances for the MPC controller were also acceotable for both controlled variables.     

Research on the Degradation Kinetics Model in the Drying Process of Chinese Herb

Curative compositions such as catolpol in Rehmannia Glutinosa, flavone in Ophiopogon Japonicus and ginsenoside Re in Panax Ginseng in Chinese herbs were measured as the experimental indices by the method of high performance liquid chromatography under different drying conditions. The reaction order and parameters of the degradation kinetics model were determined and the model was verified by experiments. It was indicated that by comparing with the thin drying method, the prospective model could predict the degradation of curative compositions with drying time, temperature and moisture content of herbal materials with enough precision and could be used to simulate the degradation in the drying process of Chinese herb.     

中草药干燥过程中质量退化动力学模型的研究

Curative compositions such as catolpol in Rehmannia Glutinosa, flavone in Ophiopogon Japonicus and ginsenoside Re in Panax Ginseng in Chinese herbs were measured as the experimental indices by the method of high performance liquid chromatography under different drying conditions. The reaction order and parameters of the degradation kinetics model were determined and the model was verified by experiments. It was indicated that by comparing with the thin drying method, the prospective model could predict the degradation of curative compositions with drying time, temperature and moisture content of herbal materials with enough precision and could be used to simulate the degradation in the drying process of Chinese herb.     

干法灰化消解和ICP-OES法测定糕点中的铝含量

介绍了两种种实用性强的测定糕点中铝含量的方法：干法灰化消解紫外分光光度计比色测定糕点中的铝含量,微波消解电感耦合等离子体发射光谱测定高点中的铝含量。结果表明：两种方法经计算加标回收率和精确度满足要求。干法灰化消解紫外分光光度计比色测定方法操作便捷,检测成本低,ICP-OES稳定性好,但是检测成本高。     

TiO2纳米管/UV/O3对腐殖酸的降解动力学

用自制的TiO₂纳米管（TNTs）作为催化剂,对腐殖酸进行TNTs/UV/O₃工艺降解研究.从动力学角度分析了光催化、臭氧化的协同作用及催化剂煅烧温度的影响,考察了反应温度、初始pH值、催化剂投加量和臭氧投加量对降解速率的影响,建立了新型动力学模型.结果表明,光催化和臭氧化有很强的协同作用,催化剂最佳煅烧温度为400℃,腐殖酸的TOC降解过程符合零级反应,模型显示当原水pH值为7.35,TNTs投加量0.806g·L^-1,O₃投加量0.49g·h^-1时TNTs/UV/O₃对腐殖酸TOC的降解取得最佳反应速率,当反应温度T为25℃时,最佳k为0.8095mg·L^-1·min^-1,当反应温度T为30℃时,最佳k为0.8231mg·L^-1·min^-1.试验结果和模型结果对比得出试验值基本符合动力学模型.     

臭氧/紫外光协同处理中低浓度氨氮废水

以臭氧/紫外光协同技术处理中低浓度氨氮废水,采用批实验对该技术处理中低浓度氨氮废水的特性进行研究,考虑了pH、臭氧流量、温度、氨氮初始浓度和反应时间对处理效果的影响。结果表明,废水中氨氮去除率随pH、臭氧流量、温度和反应时间的增大而增加,在pH 12.0、反应温度30℃、臭氧流量14.0 L/h时,反应时间120 min后氧化锰厂废水氨氮去除率达96.2%,处理后废水氨氮质量浓度由220 mg/L降至8.36 mg/L,达到GB 31573-2015直接排放标准。与臭氧、紫外光处理氨氮的对比实验表明,臭氧/紫外光协同技术表现出较高的氨氮去除效果。     

TiO2纳米管/UV/O3对腐殖酸的降解动力学

用自制的TiO₂纳米管（TNTs）作为催化剂,对腐殖酸进行TNTs/UV/O₃工艺降解研究.从动力学角度分析了光催化、臭氧化的协同作用及催化剂煅烧温度的影响,考察了反应温度、初始pH值、催化剂投加量和臭氧投加量对降解速率的影响,建立了新型动力学模型.结果表明,光催化和臭氧化有很强的协同作用,催化剂最佳煅烧温度为400℃,腐殖酸的TOC降解过程符合零级反应,模型显示当原水pH值为7.35,TNTs投加量0.806g·L^-1,O₃投加量0.49g·h^-1时TNTs/UV/O₃对腐殖酸TOC的降解取得最佳反应速率,当反应温度T为25℃时,最佳k为0.8095mg·L^-1·min^-1,当反应温度T为30℃时,最佳k为0.8231mg·L^-1·min^-1.试验结果和模型结果对比得出试验值基本符合动力学模型.     

生物酶法合成氰氟草酯过程监测的RP-HPLC分析方法的研究

为实时监控化学-酶法制备氰氟草酯反应过程,建立了一种该体系中氰氟草酯的RP-HPLC的检测方法。采用SymmetryC18柱（5μm,4.6 mm i.d.×150 mm）,以V（甲醇）∶V（水）=80∶20为流动相,流速为1.0 mL/min,紫外检测波长为282 nm,柱温为30℃,进样量为20μL。氰氟草酯在5.0~1000.0 mg/L范围内线性良好,相关系数达到0.9999,检出限为1.0 mg/L,相对标准偏差为0.58%（n=5）,加标回收率在92.3%~101.5%之间。     

高级氧化-分光光度法联合测定水中总氮总磷

提出了一种采用物理手段进行氧化消解水样的方法,对总氮总磷国标法中传统的氧化消解方法进行了改进.研究开发了一套集臭氧、紫外光、超声波、高压静放电等高级氧化技术协同的氧化消解装置,并结合分光光度法,实现了对水中总氮总磷的在线连续检测.进行了精密度检验,将检测结果与标准值进行比对,表明其具有较好的准确度.与标准方法相比,该设...     

Reaction behavior of quartz in gibbsite-boehmite bauxite in Bayer digestion and its effect on caustic consumption and alumina recovery

A high content of quartz is usually present in Australian gibbsite-boehmite bauxite. The reaction between quartz and sodium aluminate solution at high temperatures in the Bayer process can lead to loss of alumina and sodium oxide. Therefore, to improve alumina recovery, the reaction of quartz needs to be avoided. The digestion behavior of Australian gibbsite-boehmite bauxite and pure quartz in the Bayer process at 230–250 °C was systematically studied in this paper. The mineral composition and morphology of the reaction products were characterized and the kinetics of the quartz dissolution process was studied in detail. It was shown that boehmite in gibbsite-boehmite bauxite can be completely digested at high temperature (250 °C) with a short digestion time (5 min). A short digestion time results in a low reaction rate of quartz in bauxite, and is ideal for alumina recovery at high temperatures. The quartz reaction rate rapidly increases with longer digestion times. The apparent activation energy of the dissolution of quartz in bauxite in the caustic solution is 151.9 kJ mol^?1, and the rate-controlling step of this reaction process is the interfacial chemical reaction. By controlling the particle size of bauxite, the digestion temperature, and the digestion time, the reaction rate of quartz in bauxite can be inhibited, which is beneficial for improving alumina recovery and reducing caustic consumption. Therefore, based on the above theoretical research, a process for digesting gibbsite-boehmite bauxite is proposed using high digestion temperature (250 °C), short digestion time (5 min) and large mineral size. An economic benefit of about US$101.9 million for a refinery with the annual output of 2 million tons of alumina can be created by the proposed process.     

Photocatalytic degradation of humic substances in the presence of ZnO nanoparticles immobilized on glass plates under ultraviolet irradiation

ZnO nanoparticles were prepared through the chemical precipitation method and immobilized on glass plates. The effects of initial pH, UV lamp power, glass surface area, and initial humic substances (HS) concentration on the photocatalysis of HS were studied. Acidic conditions favoured the photocatalysis of HS. The degradation efficiency of HS was enhanced by increasing the UV lamp power and glass surface area. According to the results of total organic carbon (TOC) analysis, a mineralization efficiency of 59.3% was obtained within a reaction time of 120 min in comparison with the removal efficiency (%) of UV₂₅₄, which was found to be 83.3%.     

改性活性炭负载TiO2光催化降解硝基苯

制备经铁改性的活性炭负载TiO2的光催化剂,以40 W紫外线灯为光源,对硝基苯的光降解反应进行了研究。探讨了经铁改性活性炭负载TiO2光催化剂的用量、降解的反应时间、硝基苯初始浓度、溶液pH、反应温度对反应的影响。结果表明,在紫外灯光照射下,以0.01－0.08 g该催化剂处理25 mL的10－100 mg/L硝基苯溶液,均有明显的降解效果,最佳的降解时间和pH分别为40 min和6.6。