Recovery of vanadium and tungsten from waste selective catalytic reduction catalysts by K_(2)CO_(3) roasting and water leaching followed by CaCl_(2) precipitation

Waste selective catalytic reduction(SCR)catalysts are potential environmental hazards.In this study,the recovery of vanadium and tungsten from waste SCR catalysts by K_(2)CO_(3)roasting and water leaching was investigated.The roasting and leaching conditions were optimized:the leaching efficiencies of vanadium and tungsten were 91.19%and 85.36%,respectively,when 18 equivalents of K_(2)CO_(3)were added to perform the roasting at 900℃ for 2 h,followed by leaching at 90°C for 1 h.Notably,in the described conditions,the leaching rate of silicon was only 28.55%.Titanates,including K_(2)Ti_(6)O_(13)and KTi8017,were also produced.Si removal was achieved in 85%efficiency adjusting the pH to 9.5,and the Si impurity thus isolated was composed of amorphous Si.Tungsten and vanadium were precipitated using CaCl_(2).At pH 10 and following the addition of 0.10 mol of H_(2)O_(2)and 16 equivalents of CaCl_(2),the precipitating efficiencies of tungsten and vanadium were 96.89%and 99.65%,respectively.The overall yield of tungsten and vanadium was 82.71%and 90.87%,respectively.

Electrochemical Oxidation of Chlorimuron-ethyl on Ti/SnO_2-Sb_2O_5/PbO_2 Anode for Waste Water Treatment

The electrochemical oxidation of chlorimuron-ethyl on metry. The electrochemical behaviour of the electrode in a sodium Ti/SnO2-Sb2O5/PbO2 electrode was studied by cyclic voltamsulfate solution and in the mixture solution of sodium sulfate and chlorimuron-ethyl was studied. The experimental results of cyclic voltammetry show that the acidic medium was suitable for the efficient electrochemical oxidation of chlorimuron-ethyl. Some electro-generated reagent was formed in the electrolysis process and chlorimuron-ethyl could be oxidized by the electro-generated reagent. A Ti/SnO2-Sb2O5/PbO2 electrode was used as the anode and the electrolysis experiment was carried out under the optimized conditions. The electrolysis process was monitored by UV-Vis spectrometry and high performance liquid chromatography（HPLC）, and the chemical oxygen demand（COD） was determined by the potassium dichromate method. The mechanism of chlorimuron-ethyl to be oxided was studied primarily by the cyclic voltammetry and UV-Vis spectrometry. The results of electrolysis experiment demonstrate the possibility of the electrode to be used as an anode for the electrochemical treatment of chlorimuron-ethyl contained in waste water.

一种基于双硫醚转化为醛的新型Hg^(2+)荧光探针

报道了一种新型的易于合成的反应型Hg^(2+)荧光探针,根据汞离子可以使缩硫醛脱保护生成相应醛的设计合成了一个二硫醇衍生物荧光探针,在乙腈-柠檬酸缓冲溶液中,Hg^(2+)使探针发生了明显的荧光光谱变化。荧光光谱实验结果表明,探针对Hg^(2+)表现出较强的选择性和抗干扰能力。探针对Hg^(2+)的检测限达到了5.7×10^(-7)mol/L。其识别机理通过核磁、荧光和质谱等方法验证。同时探针成功地应用于自来水中Hg^(2+)的检测。

Development of emergency water quality standard for Cr^(6+) and Hg^(2+) in Liao River basin

The acute toxicity data of Cr＋ and Hg2＋ to the aquatic organisms in Liao River basin was collected and screened. Calculated results of criteria values using popular species sensitivity distribution （SSD） methods were evaluated through data analysis. The comprehensive methodology of emergency water quality standards （EWQSs） was established on the basis of the SSD method of Australia and New Zealand according to the evalu- ation results. The affected fractions of the aquatic organisms were set to be 5 %, 15 %, 30 % and 50 %, corre- sponding to the risk grades of Ⅰ,Ⅱ,Ⅲ and IV, and four-grade EWQSs, respectively. The EWQSs for Cr6＋ and Hg2. in the Liao River were derived and the corresponding risk indicators were also proposed. The results showed that the four-grade EWQSs for Cr6＋ were 2.85 μg/L, 21.0 μg/L, 161 μg/L and 797 μ/L, respec- tively, and the risk indicators were daphnia （grade Ⅱ ）, shrimp （grade Ⅲ）, and the bighead fish or tadpole （grade IV）. The four-grade EWQSs for Hg2＋ were 0.59 μg/L, 2.32 μg/L, 6.25 μg/L and 15.6 μg/L, respective- ly, and the risk indicators were crucian carp or daphnia （grade Ⅱ）, shrimp （grade Ⅲ）, and worm or crab （grade IV）. The results provided valuable information for the risk analysis of sudden ambient water environmen- tal pollution accident.

Assessment of Electric Power Generation via Water Hyacinths and Agricultural Waste

The importance and the necessary of researches on renewable energy have become a hot topic in recent years due to climate change and global warming. In addition, the fossil fuel reserves is facing rapid depletion on the earth. Currently, most researches have concentrated on producing biogas for heating, lighting, drying, cooking but lack in researching on electricity production because the possibility of producing biogas at households are common at small scale. Studying on alternative energy sources to replace traditional fuel for electric power generation brings new chances and great opportunities for development. This study presents an assessment electric power generation via water hyacinths and agricultural waste. In this paper, the evaluation electric power is generated by operating internal combustion engines which use biogas fuel to replace traditional fuel （diesel, gasoline）. The results of the studies were demonstrated by experiments on the renewable energy production system at Hoa An Biotechnology Research and Experimental Center of Cantho University.

Cd^(2+)或Hg^(2+)水污染对菱体细胞的细胞核及叶绿体超微结构的影响

用Ｃｄ２＋、Ｈｇ２＋两种重金属离子溶液培育菱（ＴｒａｐａｂｉｃｏｒｎｉｓＯｓｂｅｃｋ．）植物体后，观察体细胞的细胞核及叶绿体超微结构的变化。处理后第８天，菱浮水叶叶片和不定根细胞中细胞核的染色质与核质遭到破坏，不定根中细胞核的核仁消失。但在各处理浓度（１０μｍｏｌ／Ｌ～５０μｍｏｌ／ＬＣｄ２＋或Ｈｇ２＋）下，核膜均保持完整。叶片细胞的叶绿体基粒数目减少，基粒片层解体，叶绿体双层膜断裂，叶绿体中的质体球流入细胞基质中。两种结构的破坏程度随处理的离子浓度提高而增大。说明菱体细胞超微结构的变化观测可作为监测重金属污染的一种方法。

硫脲修饰啤酒废酵母吸附Hg^(2+)的性能

以戊二醛为交联剂,将硫脲修饰到啤酒废酵母菌上,合成了一种新型吸附剂。用电子显微镜、红外光谱以及光电子能谱对菌体的结构进行了表征。考察了交联剂用量、溶液pH值、金属离子初始浓度、吸附时间等对菌体吸附Hg2+的影响。结果表明,25℃时,修饰菌在pH值1.5条件下吸附60 min,对Hg2+的饱和吸附容量为58.9 mg.g-1,吸附过程符合准二级方程,吸附为Langmuir单分子层化学吸附。用该吸附剂处理加标准汞的自来水样,平均Hg2+吸附率为71.4%。

新型水溶性Hg^(2+)荧光探针的合成及光谱性能研究

以N,N-二甲基丙二胺、萘酰亚胺、三嗪杂环为主要原料,通过酰亚胺化、亲电取代、亲核取代等方法合成了一种水溶性1,8-萘酰亚胺荧光探针。研究了最终产物紫外吸收光谱、荧光光谱及对金属离子的识别作用。同时考察了温度,p H对探针-Hg2+体系荧光强度的影响。结果表明,产物在乙醇水溶液中能对汞离子有专一识别作用。产物对汞离子响应的线性方程为IF=49.050c+46.006,线性相关系数R=0.9946,检测限1×10-6g/m L。是一种具有水溶性良好的Hg2+荧光探针。

喹啉酮-香豆素类Hg^(2+)比色荧光探针的合成及应用

设计合成了新型喹啉酮-香豆素类比色荧光探针7-二乙氨基-3-[3-(7-二乙氨基)香豆素基-3-氧代丙烯基]喹啉-2-酮(QCO),用于检测水溶液中的Hg^(2+).探针QCO对Hg^(2+)表现出高选择性和强抗干扰性.此外,Hg^(2+)引起探针QCO溶液的颜色变化明显,可裸眼识别.比色法中,吸收值比(A_(500)/A_(380))与Hg^(2+)浓度呈良好的线性关系,其检出限为2.62×10^(-8)mol/L.荧光法中,探针QCO对Hg^(2+)的检出限为5.42×10^(-8)mol/L.经等摩尔变化(Job’s Plot)法、质谱及红外光谱验证,探针QCO与Hg^(2+)形成络合比为1∶1(摩尔比)的络合物.硅胶板实验和加标回收率实验结果表明,探针QCO可用于检测实际水样中的Hg^(2+).

罗丹明6G衍生物-谷胱甘肽荧光探针测定水中Hg^(2+)

在罗丹明6G衍生物(Rh6G2)中引入谷胱甘肽(GSH),制备了一种荧光探针Rh6G2-GSH,并基于其与Hg^(2+)识别时可发生荧光强度及吸光度的变化,分别采用荧光分光光度法和紫外-可见分光光度法测定水中Hg^(2+)的含量。在由体积比为1∶1的4-羟乙基哌嗪乙磺酸(HEPES)溶液和甲醇混合而成的缓冲溶液(pH 7)中加入Rh6G2和GSH,通过自组装反应合成荧光探针Rh6G2-GSH,将其加入到水样中,分别在优化的两种方法的仪器工作条件下测定。结果显示:荧光探针可在较宽的酸度范围内(pH 7~12)识别Hg^(2+),且受常见金属阳离子干扰小;两种方法制作的标准曲线的线性范围分别为2.5×10-5~2.5×10-4 mol·L-1和5.0×10-5~2.5×10-4 mol·L-1,检出限分别为1.39×10-9 mol·L-1和4.07×10-7 mol·L-1;对实际样品进行3个浓度水平的加标回收试验,两种方法所得的回收率分别为95.1%~120%和94.8%~100%,测定值的相对标准偏差(n=5)分别为0.46%~2.4%和0.15%~3.4%。采用四极杆-飞行时间质谱仪对荧光检测机理进行探究,发现Rh6G2-GSH在与Hg^(2+)进行不可逆的结合后,会进一步发生水解,生成一种荧光强度更高的有机酸。

Boost activation of peroxymonosulfate by iron doped K_(2-x)Mn_(8)O_(16):Mechanism and properties

Among the numerous transition metal catalysts,manganese-based compounds are considered as promising peroxymonosulfate(PMS)catalysts due to their low cost and environmental friendliness,such as cryptomelane manganese oxide(K_(2-x)Mn_(8)O_(16):abbreviation KMnO).However,the limited catalytic performance of KMnO limits its practical application.In this work,iron-doped KMnO(Fe-KMnO)was prepared by one-step hydrothermal method to optimize its catalytic performance.Compared with KMnO/PMS system,Fe-KMnO/PMS system possessed more excellent removal efficiency of tetracycline(TC).Meanwhile,the Fe-KMnO/PMS system also exhibited good practical application potential and excellent stability.The mechanism of Fe-KMnO activation of PMS was further analyzed in detail.It was found that Fe participated in the redox of high-valent Mn,which promoted the activation of PMS.Moreover,The Fe site as an adsorption site enhanced the TC enrichment ability of the catalyst,reducing the mass transfer resistance and further enhancing the TC removal ability of Fe-KMnO/PMS system.This work not only provides an excellent PMS catalyst,but also offers new insights into the mechanism of PMS activation by bimetallic manganese-based catalysts.

分子印迹-TiO_(2)光电催化降解增溶PHE废水性能研究

分别以菲(PHE)、非离子表面活性剂曲拉通X-100及两者的混合物作为模板,钛酸正丁酯为功能单体,通过溶胶-凝胶法,制备得到三种分子印迹-TiO_(2)[MIP-(TX-100)TiO_(2),MIP-(PHE)TiO_(2),MIP-(TX-100+PHE)TiO_(2)],并且制备对应的薄膜电极,用于光电催化处理模拟土壤淋洗增溶废水PHE。通过XRD、氮气吸附脱附、SEM对MIP-TiO_(2)材料及其薄膜电极进行性能表征。结果表明,MIP-(TX-100)TiO_(2)中,TX-100印迹分子的引入会改变晶体结构,出现金红石晶相TiO_(2),且其比表面积达到63.533 m^(2)/g,TiO_(2)颗粒大小及分散性较为良好,团聚现象也得到了一定的改善,其对TX-100(5 g/L)增溶的PHE(30 mg/L)溶液光电催化降解率可达74.45%。MIP-(TX-100)TiO_(2)电极对增溶废水PHE的吸附过程更符合二级动力学模型,该过程主要受化学吸附所控制。推测分子印迹过程使TiO_(2)产生大量印迹空穴,在光电催化过程中印迹空穴富集TX-100后,使PHE破除胶束障碍,从而提高了PHE的降解效率。

酸处理对凹凸棒石粘土表面及其吸附Hg(II)的影响

采用不同浓度硝酸活化改性凹凸棒石粘土(简称凹土)制备含Hg废水处理吸附剂,研究了硝酸浓度、改性凹土用量、吸附时间、pH等对改性凹土吸附去除Hg2+效果的影响,并通过比表面测定探讨了凹土改性后比表面增加的原因。结果表明:经4mol/LHNO3改性处理后的凹土吸附能力最好,凹土加入量为25g/L,水样pH=3,超声搅拌30min条件下,废水中Hg(II)的吸附率接近98%;比表面积增加归因于凹土中八面体不均匀、不连续溶解和局部四面体硅的溶蚀导致凹土孔道开放和直径扩大。

3,5-二溴-2-吡啶重氮氨基偶氮苯的合成及与镉(Ⅱ)的显色反应研究

报道了一种新型三氮烯类偶氮染料的合成方法及其与 Cd( )的显色反应。在 Triton X- 1 0 0存在下的弱碱性介质中 ,该试剂与 Cd( )形成 4∶ 1的红色络合物 ,最大吸收波长位于 52 6nm 处 ;表观摩尔吸收系数为 2 .0 4× 1 0 5L·mol-1·cm-1,镉含量在 0～ 1 5μg/ 2 5m L范围内符合比耳定律。方法可直接用于废水中微量镉的测定。

新显色剂4-甲基-2-磺酸基苯基重氮氨基偶氮苯的合成及与镉的显色反应研究

报道了新显色剂４－甲基－２－磺酸基苯基重氮氨基偶氮苯的合成及其与Ｃｄ（Ⅱ） 的显色反应。实验表明，在非离子表面活性剂Ｔｒｉｔｏｎ Ｘ－１００存在下，于ｐＨ １０．８ 的氨水－氯化铵缓冲介质中，试剂与Ｃｄ（Ⅱ） 形成３∶１ 的红色络合物，最大吸收波长位于５２２ ｎｍ 处，Ｃｄ（Ⅱ） 含量在０～２０μｇ／２５ｍ Ｌ范围内符合比耳定律，表观摩尔吸光系数为２．０５ ×１０５ Ｌ·ｍ ｏｌ－ １·ｃｍ － １。已直接用于废水中微量镉的测定。

没食子酸强化Fenton体系对水中DEET降解的研究

针对Fenton反应过程中生成的Fe^(3+)的还原速率相对于Fe^(2+)和H_(2)O_(2)的反应速率较慢限制了其降解效率的问题,以N,N-二乙基-间甲苯酰胺(DEET)为目标污染物,比较了3种络合剂对Fenton反应的促进效应。结果表明,在DEET浓度为200μmol/L、H_(2)O_(2)/Fe^(2+)摩尔比为20∶1、初始Fe^(2+)浓度为50μmol/L、没食子酸(GA)/Fe^(2+)摩尔比为1∶1以及pH=7.0的条件下,DEET的去除效率在20 min内达到75.3%。与传统的Fenton体系相比,DEET的降解效率提高了63.8%。HO·是加速DEET降解和矿化的主要活性氧物质。GA促进了Fe^(3+)的还原和H_(2)O_(2)的分解,从而促进了额外自由基的生成,加速了Fe^(2+)/H_(2)O_(2)体系对DEET的降解。

新显色剂2,6-二溴-4-氨磺酰基苯基重氮氨基偶氮苯与镉(Ⅱ)的分光光度研究及其分析应用

本文报道了新显色剂2,6-二溴-4-氨磺酰基苯基重氮氨基偶氮苯与镉(Ⅱ)的显色反应。研究表明,在Triton X-100的存在下,于pH11.0的硼砂-氢氧化钠介质中,该试剂与镉(Ⅱ)可生成稳定的红色络合物,其最大吸收波长位于530nm处,摩尔吸光系数为2.02×10~5。镉(Ⅱ)量在0～10μg/25mL范围内符合比尔定律。方法曾用于煤矸石及工业废水中痕量镉(Ⅱ)的测定,获得满意的结果。

农业废弃物分解产生CO_2的影响因素研究

在正交预备试验得出有机废弃物分解产生CO2 适宜条件的基础上 ,逐一进行单因子试验 ,以获得利用农业废弃物分解产生的CO2 进行棚室栽培CO2 施肥的最适发酵条件 .结果表明 ,利用有机废弃物(稻草 +猪粪 )生物发酵产生CO2 的最佳条件分别为 :温度 5 0℃、含水量 70 %、初始 pH 6 0～ 7 0 .初始C/N比因发酵目的不同有较大变化 ,以堆肥为目的时为 30 / 1,而以产生CO2 为目的时 ,则以 4 0 / 1为宜 .在 4个因素中 ,初始C/N比和含水量对CO2 释放的影响较大 ,其次是温度 ,初始

长泥龄改良A^2/O工艺的短程硝化反硝化除磷

为解决传统A2/O工艺硝化与除磷泥龄(SRT)之间的矛盾,进一步提高低C/N(P)比生活污水同步脱氮除磷效率,采用一种改良A2/O工艺在长SRT条件下处理生活污水。试验结果表明,该工艺可有效筛选和强化反应器内活性污泥,并大量富集长SRT的反硝化除磷菌(DPAO)。通过亚硝酸盐氧化菌(NOB)淘洗阶段后,反应器在SRT=19.6d、A2O段污泥浓度(MLSS)=5.5 g·L-1、水力停留时间(HRT)=8.2 h、污泥回流比(R)=90%、硝化液回流比(r)=250%、溶解氧(DO)=1.5~0.3 mg·L-1,间歇曝气段HRT=4 h、曝气周期1 h曝气1 min(DO=0.3~0.5 mg·L-1)、沉淀59 min条件下长期运行,COD、NH+4-N、TP和TN的平均去除率分别为88.71%、99.2%、93.77%和89.52%,出水亚硝化率(NO-2-N/NO-x-N)可达97.2%,DPAO占聚磷菌(PAO)比为95.5%。污水中约72.96%的COD被DPAO合成PHA除磷,15.75%的COD由异养反硝化消耗,约41.96%和31.31%的N分别通过反硝化除磷和异养反硝化去除。剩余污泥主要由DPAO和反硝化菌增殖产生,分别占82.74%和17.24%,较传统脱氮除磷途径减少了58.76%的碳源消耗和44.6%的污泥排放。

高灵敏高选择性测镉新试剂——2-氯-4-硝基苯基重氮氨基偶氮苯的合成及应用

本文报道了高灵敏度高选择性测镉新试剂——2-氯-4-硝基苯基重氮氨基偶氮苯的合成、纯化及结构鉴定。研究了该试剂在不同表面活性剂存在下的酸性离解行为及其与镉(Ⅱ)的显色反应。实验结果表明,在Triton x-100存在下,于pH7.80的磷酸二氢钾-氢氧化钠缓冲介质中。镉(Ⅱ)可与该试剂形成稳定的红色配合物,其最大吸收波长位于505mm处,摩尔吸光系数为1.57×10~5L·mol^(-1)·cm^(-1)镉量在0～12μg/25mL范围内符合比尔定律。在所拟测定条件下,方法选择性甚佳,只有Ag^+、Hg^(2+)、Cu^(2+)离子产生干扰,可通过加入适当的掩蔽剂予以消除。方法可不经分离直接用于环境水样、工业废水及铝合金标样中痕量镉(Ⅱ)的测定,结果满意。