Use of catalytic wet air oxidation (CWAO) for pretreatment of high-salinity high-organic wastewater

Catalytic wet air oxidation(CWAO)coupled desalination technology provides a possibility for the effective and economic degradation of high salinity and high organic wastewater.Chloride widely occurs in natural and wastewaters,and its high content jeopardizes the efficacy of Advanced oxidation process(AOPs).Thus,a novel chlorine ion resistant catalyst Bsite Ru doped LaFe_(1-x)Ru_(x)O_(3-)δin CWAO treatment of chlorine ion wastewater was examined.Especially,LaFe_(0.85)Ru_(0.15)O_(3-δ)was 45.5% better than that of the 6%RuO_(2)@TiO_(2)(commercial carrier)on total organic carbon(TOC)removal.Also,doped catalysts LaFe_(1-x)Ru_(x)O_(3-)δshowed better activity than supported catalysts RuO_(2)@LaFeO_(3) and RuO_(2)@TiO_(2) with the same Ru content.Moreover,LaFe_(0.85)Ru_(0.15)O_(3-)δhas novel chlorine ion resistance no matter the concentration of Cl^(−) and no Ru dissolves after the reaction.X-ray diffraction(XRD)refinement,X-ray photoelectron spectroscopy(XPS),transmission electron microscope(TEM),and X-ray absorption fine structure(XAFS)measurements verified the structure of LaFe_(0.85)Ru_(0.15)O_(3-)δ.Kinetic data and density functional theory(DFT)proved that Fe is the site of acetic acid oxidation and adsorption of chloride ions.The existence of Fe in LaFe_(0.85)Ru_(0.15)O_(3-)δcould adsorb chlorine ion(catalytic activity inhibitor),which can protect the Ru site and other active oxygen species to exert catalytic activity.This work is essential for the development of chloride-resistant catalyst in CWAO.

Synthesis of Iron Chlorophyllins and Their Catalytic Performance for Aerobic Oxidation of Cyclohexene

A series of iron（III） chlorophyllins was prepared from silkworm excrement crude chlorophyll extract as a raw material. Aerobic oxidation of cyclohexene by using the prepared iron（III） chlorophyllins as biomimetic catalysts was studied under atmospheric pressure in the absence of reducing agent and solvent. The results indicate that chloro- phyll iron porphyrins have better catalytic performance than the industrial-applied iron tetraphenylporphyrin and cobalt tetraphenylporphyrin, and possess a higher selectivity for 2-cyclohexen-1-one. The smaller the polarity of iron（III） chlorophyllin＇s ligand is, the easier the catalytic oxidation of cyclohexene will be. Esterification products of iron（III） chlo- rophyllins can catalyze the oxidation of cyclohexene better than non-esterified iron（III） chlorophyllins, and therefore show a higher conversion of cyclohexene and a higher selectivity for 2-cyclohexen-l-one than the non-esterified ones. Among the six synthesized iron（III） chlorophyllin catalysts, iron（III） methyl-pyropheophorbide-a is the best biomimetic catalyst for the highest conversion of cyclohexene. The influences of catalyst＇s substituent, polarity and ring structure on the catalytic performance were discussed. The catalytic performance of iron（III） chlorophyllins improves with decreasing polarity, increasing conjugated degree of porphyrin＇s ring or enhancing chlorophyllins＇ stability. Possible mechanism of cyclohexene aerobic oxidation catalyzed by iron（III） chlorophyllins was also discussed.

Fe203-CeO2-Bi203/y-AI203 catalyst in the catalytic wet air oxidation （CWAO） of cationic red GTL under mild reaction conditions

The Fe203-CeO2-Bi203/-A1203 catalyst, a novel environmental-friendly material, was used to investigate the catalytic wet air oxidation （CWAO） of cationic red GTL under mild operating conditions in a batch reactor. The catalyst was prepared by wet impregnation, and characterized by special surface area （BET measurement）, X-ray diffraction （XRD） and X-ray photoelectron spectroscopy （XPS）. The Fe203-CeO2-]]i203/qt-A1203 catalyst exhibited good catalytic activity and stability in the CWAO under atmosphere pressure. The effect of the reaction conditions （catalyst loading, degradation temperature, solution concentration and initial solution pH value） was studied. The result showed that the decolorization efficiency of cationic red GTL was improved with increasing the initial solution pH value and the degradation temperature. The apparent activation energy for the reaction was 79 kJ. mo1-1. Hydroperoxy radicals （HO2.） and superoxide radicals （O2-） appeared as the main reactive species upon the CWAO of cationic red GTL.

锂电池三元前驱体的原料制备过程中萃取废水处理工艺设计

介绍了四川某三元前驱体合成前原料制备萃取工段废水处理的工艺流程及设计参数。针对该废水的水质特点,采用气浮除油、化学沉淀除重金属、臭氧催化氧化除COD、树脂深度除重金属和MVR蒸盐相结合的处理工艺,产出工业无水硫酸钠产品(纯度95%,Ⅲ类合格品),且实现废水零排放,对同类工业废水的处理具有重要参考价值。

“铁盐+空气”催化氧化体系在绿色交叉偶联反应中的应用——推荐一个本科生科研训练项目

为深入开展创新创业教育与实践,培养学生创新创业能力,提高本科生人才培养质量,进一步推动创新创业教育改革,南开大学开展了“国家级大学生创新创业训练计划”项目。化学学院结合学科自身特点,践行科教融合、理论联系实际的培养方法,不仅能够引导本科生积极参加科研训练,还能将本科生的创新结果应用于实际生产中。实现“科研反哺教学”与“教学支撑科研”这样一个相互补充、相互促进的统一体。本文介绍了一组比较典型的本科生参与“国创”项目的例子,从项目准备入手介绍了该“国创”项目的具体实施过程、同学们所遇困难及收获心得等,希望将我们积累的一些经验与化学相关专业的同学分享,助力他们更好地完成创新项目。

Mesoporous iron oxide-silica supported gold catalysts for low-temperature CO oxidation

Mesoporous iron oxide-silica composite with a high silica content was synthesized by hydrothermal method,and another composite material with a high iron content was obtained by etching part of silica in alkaline solution.Gold catalysts were loaded onto both composites by a deposition-precipitation method,and used for CO oxidation.The samples were characterized by BrumauerEmmet-Teller(BET),X-ray diffraction(XRD),X-ray photoelectron spectra(XPS),transmission electron microscope(TEM)and scanning electron microscope(SEM)techniques.Both composites had high specific surface areas and were amorphous.The Au nanoparticles dispersed on the surface of the composites existed in metallic state.Composite with high silica content was not suitable for Au loading,and its supported gold catalyst showed poor performance in catalytic reaction.In contrast,composite with high iron content allowed efficient Au loading,and CO could be oxidized completely at low temperature on its supported gold catalyst.The effects of deposition-precipitation pH values on Au loading and activity of the catalyst were investigated,and the results indicated that Au loading was the highest and the catalyst was the most active for CO oxidation when the synthesis pH was adjusted to 8.

无溶剂法Cu(Ⅱ)或Fe(Ⅲ)盐催化氧化苯甲醇制备苯甲酸

在无溶剂条件下,以无机盐CuSO4,Cu(NO3)2.3H2O,CuCl2.2H2O,FeCl3.6H2O为催化剂、以空气中的O2为氧化剂,通过苯甲醇氧化反应制备了苯甲酸。考察了无机盐种类、反应时间、催化剂用量与苯甲酸收率的关系,研究了催化剂的回收与循环使用情况,并对反应机理进行了推测。实验结果表明,Cu(Ⅱ)无机盐的催化活性高于Fe(Ⅲ)无机盐;Cu(Ⅱ)无机盐在无溶剂条件下可有效催化苯甲醇的氧化反应高收率制得苯甲酸。在苯甲醇用量为0.02mol、CuSO4与苯甲醇的摩尔比为0.082、NaOH用量0.0250mol、反应时间90min的条件下,苯甲酸收率最高,达到98.4%。该反应过程中无废弃物排放,属于环境友好的绿色化学反应。

ZnFe_(0.25)Al_(1.75)O_4催化剂在苯酚催化湿式氧化中的活性和稳定性

利用溶胶-凝胶法制备了ZnFe0.25Al1.75O4尖晶石复合氧化物催化剂,并将其用于苯酚催化湿式氧化反应.结果表明,这种催化剂对苯酚降解有较好的催化活性和稳定性.连续反应5次后,苯酚转化率为100%,COD去除率为88.7%.反应过程中,铁离子的溶出量先增加后减小,最终的出水金属离子浓度很低.第5次反应后的出水铁离子浓度为2.15 mg/L,锌离子浓度为1.53 mg/L.

溶胶凝胶法制备铜系催化剂及其稳定性研究

利用溶胶凝胶法制备超细催化湿式氧化铜系催化剂,考察了制备过程中各个工艺参数对铜系催化剂稳定性的影响,重点考察了不同分子量聚丙烯酸络合剂对催化剂稳定性及粒径的影响,应用BET以及SEM等技术手段,对催化剂的物相结构、表面孔结构和粒子形貌等进行了研究。结果表明,该催化剂对处理焦化废水具有优良的反应活性,且金属离子溶出量低,是一种极具应用前景的高效催化剂。

乳化液废水的均相催化湿式氧化

在2 L的高温高压反应釜中,以非贵的过渡金属盐作均相催化剂,研究了高浓度难降解的乳化液废水的催化湿式氧化。试验发现,单一金属盐催化活性为Cu2+>Mn2+>Co2+,其中Cu2+在200℃时催化效果良好,可使TOC去除率提高13.3%;Cu2+受投量影响较明显,以200 mg/L为宜;混合盐催化活性为Cu2++Mn2+≈Mn2++Co2+(>Cu2+)>Cu2++Co2+。

Fe_(0.5)Zn_(0.5)Al_2O_4尖晶石催化剂催化湿式氧化降解苯酚的稳定性

研究了Fe0.5Zn0.5Al2O4尖晶石型复合氧化物催化剂在催化湿式氧化处理苯酚废水中的性能.结果表明,在150℃下苯酚就能完全被去除,COD去除率达到94%.催化剂中铁的溶出量随着反应时间的增加经历了一个先增加后减小的过程;而且最终出水铁离子浓度随催化剂用量、氧分压、苯酚溶液pH值的增加而减少,随苯酚浓度的增加而增加.

Cu-Ce/Al_2O_3湿式氧化催化焦化废液的工艺条件探讨

利用Cu-Ce/Al_2O_3催化剂处理焦化废液时,该催化剂的加入可使焦化废液COD去除率明显提高,处理效果随温度升高明显增强。在保证氧气供应充足的情况下,适当增加氧气分压对COD去除率增加贡献不大。其优化工艺条件为:总压4.9 MPa,反应温度190℃,氧气分压1.8 MPa,氧化反应时间120 min,废液COD最高去除率可达91.9%,且金属离子溶出量较少,Cu^(2+)溶出量为0.2655 mg·L^(-1),Ce^(4+)溶出量为0.0813mg·L^(-1),该催化剂持续工作500 h内,其催化活性和稳定性良好。

高浓度苯酚废水的均相催化湿式氧化研究

在13L高压反应器中，以非贵金属盐作为均相催化剂，以高浓度苯酚有机废水为处理对象，研究了高浓度难降解酚类废水的催化湿式氧化。结果表明，单一金属盐催化活性为Cu^2＋〉Zn^2＋〉Mn^2＋催化湿式氧化适用于较宽的初始COD浓度范围（20000—60000mg／L）；铜盐的均相催化湿式氧化最佳工艺条件为220℃、2．5MPa、pH6．0，2h的COD去除率可达到97．2％。

常压/低压湿空气催化氧化氯乙酸降解机理

利用无机熔盐水合物的温升效应,考察了氯乙酸废水在常压/低压下湿空气催化氧化降解效果,分别探讨了催化剂种类、反应温度、反应时间对氯乙酸和COD(化学需氧量)去除率的影响,并对反应机理进行了初步探讨。结果表明,在CaCl_(2)·2H_(2)O熔盐水合物中CuCl_(2)对氯乙酸的降解效果最佳,在200℃和0.35MPa条件下氯乙酸去除率可达97.2%,COD去除率可达90.7%。通过自由基抑制实验和中间产物分析推测反应机理为:在羟基自由基的协同催化下,氯乙酸依次降解为羟基乙酸、二羟基乙酸、甲酸、CO_(2)和水。