锆负载树脂用于含氟废水深度处理的研究

本文研制了一种以火力发电厂废树脂为载体的锆负载型氟离子吸附剂，并在评价了该树脂以氟离子的吸附性能之后探讨了该树脂用于火力发电厂含氟废水深度处理的可能性。研究结果表明，锆的最佳负载的最佳浓度为0．5mol／L，该负载树的最佳吸附pH为3．0－4．0，用填充柱进行的实验结果表明，pH＝3的吸附容量显著高于pH＝4时的值。利用该树脂对火力发电厂模拟含氟废水进行了双柱串联吸附工艺处理，当柱流量为35mL／min（SV10）、第二穿透时，第一柱的吸附容量为10228mg／L显著脂；用0．1mol／L的NaOH溶液进行再生，柱流量选择为35mL/min（SV10）时，脱附率在95％以上。     

锆(Ⅳ)负载交联壳聚糖吸附硫酸根的性能

以甲醛、苯甲醛为交联剂,制备交联壳聚糖树脂,再与锆(Ⅳ)离子反应制备锆负载交联壳聚糖吸附剂。采用静态吸附法考察了该吸附剂对水中硫酸根离子(SO24-)的吸附性能。实验发现,吸附时间2 h,SO24-溶液初始浓度500 mg/L,pH值3.0,溶液温度35℃为较优的吸附条件;吸附过程符合Langmuir等温吸附模型,属于优惠吸附型,吸附容量可达78.65 mg/g;吸附过程较好地符合拟二级动力学模型;锆负载前后交联壳聚糖对硫酸根的吸附量提高了约4.5倍;该吸附剂具有良好的耐酸性和再生性能。     

树脂吸附法处理硫化促进剂CA生产废水的研究

采用特种吸附树脂处理促进剂CA生产废水 ,系统地研究了废水的pH值、吸附温度及吸附流量等因素对树脂吸附性能的影响 ,以及以稀硫酸为脱附剂 ,其配比、流量、温度等对树脂脱附性能的影响。实验结果表明 ,特种吸附树脂对该废水具有良好的吸附 脱附效果 ,废水经吸附处理后 ,CODCr浓度由 2 0 0 0 0mg/L左右降至 30 0mg/L以下 ,CODCr去除率达98%以上。该工艺简单 ,运行稳定 ,操作简便 ,可望实现工业化。     

季铵化改性木屑纤维素的制备及对氟离子的吸附研究

以3-氯-2-羟丙基三甲基氯化铵(CTA)为醚化剂,对木屑纤维素进行了季铵化改性.探讨了季铵化改性木屑纤维素用量、pH、吸附温度、氟离子初始浓度和吸附时间对氟离子静态吸附率的影响,以及流速对氟离子动态吸附率的影响.结果表明:(1)静态吸附最佳工艺条件:季铵化改性木屑纤维素用量为3.0 g/L,pH为4.0～6.0,吸附温度为25 ℃,吸附时间为120 min.在此最佳工艺条件下,季铵化改性木屑纤维素对100 mL 50.00 mg/L氟离子溶液的吸附率最高可达90.11%.(2)在pH为5.0、25 ℃的条件下,将50.00 mg/L氟离子溶液以5 mL/min的流速流经装有3.0 g/L季铵化改性木屑纤维素的吸附柱,吸附率可达97.95%.(3)季铵化改性木屑纤维素对溶液中氟离子的吸附过程为放热过程,在吸附过程中存在着化学吸附.(4)木屑来源丰富、价格价廉,季铵化改性木屑纤维素对溶液中氟离子的吸附效果好,且吸附工艺简单、易于实现工业化,具有良好的应用前景.     

负载TiO2的活性炭纤维改性电极电吸附除氟

采用溶胶-凝胶法制备TiO2凝胶,将TiO2凝胶涂覆在活性炭纤维表面并进行热处理制备改性电极(TiO2/ACF),利用扫描电子显微镜(SEM)、X射线衍射光谱仪(XRD)、比表面和孔隙度分析仪对负载前后电极的表面特性进行表征,并探讨了其对NaF溶液的电吸附效果。结果表明,电极负载TiO2后表面变得粗糙,比表面积和总孔体积减小,而介孔体积和平均孔径增大。此外,表面的TiO2同时以金红石和锐钛矿的晶型存在。电吸附实验结果显示,加电可以提高吸附容量,而且电压、pH和初始氟离子浓度均对电吸附容量产生影响:电压增大,吸附容量增加,当施加电压为2 V时,电吸附容量为1.03 mg/g,比开路电位时提高40%;pH可以通过影响氟离子在溶液中的存在形态和TiO2/ACF电极表面的羟基基团对电吸附容量产生影响;初始氟离子浓度升高,电极吸附容量增大,但是去除率降低。在处理初始氟离子浓度为4 mg/L的NaF溶液时,在2 V电压、中性pH和12 h的吸附时间下,改性ACF为电极的吸附量为1.32 mg/g。     

负载TiO_2的活性炭纤维改性电极电吸附除氟

采用溶胶-凝胶法制备TiO2凝胶,将TiO2凝胶涂覆在活性炭纤维表面并进行热处理制备改性电极（TiO2/ACF）,利用扫描电子显微镜（SEM）、X射线衍射光谱仪（XRD）、比表面和孔隙度分析仪对负载前后电极的表面特性进行表征,并探讨了其对NaF溶液的电吸附效果。结果表明,电极负载TiO2后表面变得粗糙,比表面积和总孔体积减小,而介孔体积和平均孔径增大。此外,表面的TiO2同时以金红石和锐钛矿的晶型存在。电吸附实验结果显示,加电可以提高吸附容量,而且电压、pH和初始氟离子浓度均对电吸附容量产生影响：电压增大,吸附容量增加,当施加电压为2 V时,电吸附容量为1.03 mg/g,比开路电位时提高40%;pH可以通过影响氟离子在溶液中的存在形态和TiO2/ACF电极表面的羟基基团对电吸附容量产生影响;初始氟离子浓度升高,电极吸附容量增大,但是去除率降低。在处理初始氟离子浓度为4 mg/L的NaF溶液时,在2 V电压、中性pH和12 h的吸附时间下,改性ACF为电极的吸附量为1.32 mg/g。     

菌丝体表面分子印迹壳聚糖吸附剂对Cr3+的吸附性能研究

菌丝体表面分子印迹吸附剂所保留的印迹对过渡金属离子有着良好的吸附作用,以Cr3 作为吸附离子,系统研究了该吸附剂的吸附特性和影响因素.结果表明:吸附剂对Cr3 的饱和吸附容量可达60 mg/g;其吸附行为满足Langmuir方程式.初始浓度为200 mg/L时,最佳吸附pH在3～4,吸附容量可达到50 mg/g左右,离子强度对吸附没有影响,用0.5 mol/L硝酸或硫酸解吸Cr3 ,解吸率在90%以上.     

电增强载铝活性炭纤维吸附氟离子性能

以载铝活性炭纤维毡为电极,在电场作用条件下对模拟含氟水进行静态吸附实验。结果表明,该载铝活性炭纤维毡正极化可以强化吸附除氟效果,吸附动力学数据很好地符合Lagergren二级速率方程,加电场时二级反应速率常数为4.50 g/(mg·h);其对高浓度含氟饮用水也有较高去除率,Freundlich吸附等温方程能很好地描述吸附平衡数据。加电场情况下,该载铝炭毡对氟离子的最大吸附量为16.584 mg/g,去除氟离子的最佳pH范围是5.5~8.9。共存阴离子Cl-、SO2-4和NO-3对炭毡吸附除氟没有抑制作用,但CO2-3的存在会导致除氟吸附量显著下降。     

三维电极电吸附动态反应器的除氟特征研究

采用自制的单极性复合型三维阳极作为第三维电极对含氟水进行动态电促吸附实验,通过研究不同填充床高度、阴阳极板间距、隔膜材料对电促吸附除氟效果的影响,确定反应器的最佳结构参数为:填充床高度20 cm、阴阳极板间距4 cm、隔膜为nafion117膜。工作电压、进水pH、进水流速、共存物质对氟离子去除效果的影响结果表明:在一定范围内增大工作电压,降低进水pH或进水流速均可提高除氟效果。相应的最佳操作条件为:工作电压7 V、进水流速4 mL/min、酸性pH;腐殖酸和碳酸根离子的存在会对氟离子去除产生较强抑制作用,低浓度的氯离子可促进氟离子的电促吸附。扫描电镜(SEM)-电子能谱(EDX)的表征结果显示三维颗粒电极的表面及孔隙内部均可吸附氟离子,且电吸附后并未出现电极腐蚀现象。     

001×14.5离子交换树脂对镍(Ⅱ)的吸附

实验采用离子交换树脂法吸附镍(Ⅱ),树脂选型确定了强酸性阳离子交换树脂001×14.5对镍(Ⅱ)吸附容量最大.用所选的001×14.5树脂吸附镍(Ⅱ)的过程,静态吸附实验表明,转速大于100 r/min时,对树脂吸附的影响可忽略,即基本消除外扩散,pH =7.0时吸附最佳,镍(Ⅱ)吸附率随树脂用量的增加而增大;001×14.5树脂吸附镍(Ⅱ)过程符合Langmuir等温吸附方程,且为优惠吸附;吸附过程符合拟二级动力学模型,吸附过程活化能为E=30.9 kJ/mol,由颗粒内扩散控制;用1 mol/L的硫酸对吸附饱和树脂进行脱附再生,脱附率可达98％以上.     

Crystalline hydrous ferric oxide: an adsorbent for chromium(VI)-contaminated industrial wastewater treatment.

Synthetic crystalline hydrous ferric oxide (CHFO) (particle size 0.14 to 0.29 mm) has been used systematically for adsorptive chromium(VI) removal from contaminated water. Batch experiments were performed as a function of pH, contact time, solute concentration, and regeneration of adsorbents. Column experiments were performed for breakthrough points in the presence and absence of other ions and treatment of industrial effluent. The optimum pH range was 2.0 to 4.0. The adsorption kinetic data could be described well by both second-order and pseudo-first-order models. The isotherm adsorption data at 30 +/- 2 degrees C obeyed the Langmuir model best. The monolayer adsorption capacity was 35.7 mg/g. Chromium(VI)-rich CHFO could be regenerated up to 89 +/- 1% with 2.0 M sodium hydroxide. Regenerated column reuse showed a decrease (10 to 12%) in breakthrough capacity. Finally, the CHFO- (dried at 300 degrees C) packed column was used for the recovery (98.5 +/- 1.0%) of chromium(VI) from contaminated industrial waste effluent of Hindustan Motor Limited (Hooghly, West Bengal, India).     

Breakthrough adsorption study of migratory nickel in fine-grained soil.

The present study was conducted to evaluate the breakthrough curve for nickel adsorption in fine-grained soil from a nearby ash pond site of a thermal power plant. Nickel was found to be the major polluting solute in the ash sluicing wastewater. The adsorption of nickel by vertical soil column batch test and horizontal migration test was carried out in the laboratory. Field investigation was conducted also, by installing test wells around the ash pond site. Experimental results showed a good adsorptive capacity of soil for nickel ions. The breakthrough curves showed a reasonable fitting with a one-dimensional mathematical model. The breakthrough curves yielded from field test results showed good agreement with a two-dimensional mathematical model.     

Fluoride removal performance of a novel Fe-Al-Ce trimetal oxide adsorbent

A trimetal oxide was developed as a fluoride adsorbent by coprecipitation of Fe(II), Al(III) and Ce(IV) salt solutions with a molar ratio of 1:4:1 under alkaline condition. The material retained amorphous structure and maintained relatively stable fluoride adsorption performance at calcination temperatures lower than 600 degrees C. The optimum pH range for fluoride adsorption was 6.0-6.5 and the adsorbent also showed high defluoridation ability around pH 5.5-7.0, which is preferable for actual application. A high fluoride adsorption capacity of 178 mg g(-1) was acquired under an equilibrium fluoride concentration of 84.5 mg l(-1), adsorbent dose of 150 mg l(-1) and pH 7.0. The adsorption isotherm could be better described by the two-site Langmuir model than the one-site model, suggesting the existence of two types of active sites on the adsorbent surface. Coexistence of high concentrations of phosphate or arsenate only led to partial inhibition of fluoride adsorption, which further suggests the existence of heterogeneous adsorption sites. Sulfate and chloride did not affect fluoride adsorption, and nitrate influenced it only when the concentration of NO(3)(-)-N exceeded 50 mg l(-1). A high desorption efficiency of 97% was achieved by treating fluoride loaded Fe-Al-Ce oxide with NaOH solution at pH 12.2. A column experiment using the adsorbent fabricated into 1mm pellets was performed at an initial fluoride concentration of 5.5 mg l(-1), space velocity of 5h(-1) and pH of 5.8, and 2240 bed volumes were treated with the effluent fluoride under 1.0 mg l(-1).     

Column dynamic studies and breakthrough curve analysis for Cd(II) and Cu(II) ions adsorption onto palm oil boiler mill fly ash (POFA)

This paper investigates the adsorption characteristics of palm oil boiler mill fly ash (POFA) derived from an agricultural waste material in removing Cd(II) and Cu(II) from aqueous solution via column studies. The performance of the study is described through the breakthrough curves concept under relevant operating conditions such as column bed depths (1, 1.5, and 2 cm) and influent metal concentrations (5, 10, and 20 mg/L). The Cd(II) and Cu(II) uptake mechanism is particularly bed depth- and concentration-dependant, favoring higher bed depth and lower influent metal concentration. The highest bed capacity of 34.91 mg Cd(II)/g and 21.93 mg Cu(II)/g of POFA was achieved at 20 mg/L of influent metal concentrations, column bed depth of 2 cm, and flow rate of 5 mL/min. The whole breakthrough curve simulation for both metal ions were best described using the Thomas and Yoon–Nelson models, but it is apparent that the initial region of the breakthrough for Cd(II) was better described using the BDST model. The results illustrate that POFA could be utilized effectively for the removal of Cd(II) and Cu(II) ions from aqueous solution in a fixed-bed column system.     

Heavy metals removal in fixed-bed column by the macro fungus Pycnoporus sanguineus

The ability of Pycnoporus sanguineus to adsorb heavy metals from aqueous solution was investigated in fixed-bed column studies. The experiments were conducted to study the effect of important design parameters such as column bed height, flow rate and initial concentration of solution. The breakthrough profiles were obtained in these studies. A mathematical model based on external mass transfer and pore diffusion was used for the prediction of mass transfer coefficient and effective diffusivity of metals in macro-fungi bed. Experimental breakthrough profiles were compared with the simulated breakthrough profiles obtained from the mathematical model. Bed Depth Service Time (BDST) model was used to analyse the experimental data and evaluated the performance of biosorption column. The BDST model parameters needed for the design of biosorption columns were evaluated for lead, copper and cadmium removal in the column. The columns were regenerated by eluting the metal ions using 0.1 M hydrochloric acid solution after the adsorption studies. The columns were subjected to repeated cycles of adsorption of same metal ions and desorption to evaluate the removal efficiency after adsorption-desorption.     

Lead removal in fixed-bed columns by zeolite and sepiolite

The removal efficiency of zeolite (clinoptilolite) and sepiolite from lead containing aqueous solutions was investigated. A series of experiments were conducted in batch-wise and fixed-bed columns. Synthetic wastewaters containing lead (50 mg l (-1)) and acetic acid (0.001 N) along with untreated and regenerated clinoptilolites and sepiolites were used in the adsorption studies. Batch tests were mainly conducted to isolate the magnitude of lead precipitation from real adsorption. Adsorption isotherms for both abstraction and adsorption were constructed. The removal of lead is found to be a sum of adsorption induced by ion exchange and precipitation of lead hydroxide. The breakthrough curves were obtained under different conditions by plotting the normalized effluent lead concentration (C/C0) versus bed volume (BV). The ion exchange capacity of sepiolite and clinoptilolite for lead removal showed good performance up to approximately 100 and 120 BV where the C/C0 remained below 0.1, respectively. The lead removal capacity of clinoptilolite bed from wastewater containing only lead yielded 45% higher performance compared to that of acetic acid partly due to a decrease in the effluent pH and consequently in precipitation. Also, the presence of acetic acid in the sepiolite column decreased the bed volumes treated by about 40%. Removal efficiency of lead-acetic system both in untreated clinoptilolite and sepiolite columns was found higher than that in regenerated columns.     

Validation studies of an automated preconcentration water sampler (APS) for chlorinated dibenzo-p-dioxins and dibenzofurans

An Automated Preconcentration Sampler (APS) was developed by the Ontario Ministry of the Environment (MOE) and Carleton University for the determination of polychlorinated dibenzo-p-dioxins (PCDDs) and polychlorinated dibenzofurans (PCDFs) in drinking water. The APS employs a two-stage particulate filtration system followed by an XAD-2 resin column. Field and laboratory testing of the APS is required to validate the device before it is put into regular service.The capacity of the APS filtration system is 30 L for a 4 Formazin Turbidity Unit (FTU) input water turbidity and greater than 50 L for a typical treated water. Flushing of a clean XAD-2 resin column with 200 L of spiked water showed that the optimum flowrate in terms of spike breakthrough is equal to three times the resin bed volume per minute. This flowrate is used for APS operation. Testing also showed that no spike breakthrough occurred after 200 L of clean water was flushed through a spiked XAD-2 resin column at flowrates in excess of the APS operating flowrate. Spike testing was also carried out on the filters and results are pending. An analytical comparison between the present MOE sampling and analytical procedure and the proposed APS sampling and analytical procedure using a PCDD/PCDF source water is planned.     

盐酸和硝酸介质中己二胺接枝壳聚糖微球吸附Hg(Ⅱ)的行为

制备并表征了氯化和氨化壳聚糖微球,考察了己二胺接枝壳聚糖微球(HDA-CS)在盐酸和硝酸介质中吸附Hg(Ⅱ)的行为及影响因素。结果表明,盐酸介质中,pH 3.0时,HDA-CS对Hg(Ⅱ)有较高的初始吸附速率,最大吸附容量为128.6 mg/g;硝酸介质中,pH 3.5时,它对Hg(Ⅱ)的最大吸附容量为37.7 mg/g。前者是后者的3.4倍。以1.0 mol/L的H2SO4为解吸剂,HDA-CS复用3次无溶解和流失现象。HDA-CS对Hg(Ⅱ)的吸附主要是质子化氨基与汞配阴离子以静电引力实现的。     

多孔镁铝复合氧化物对水溶液中Cr（VI）的吸附性能

摘要以镁盐、铝盐、纯碱和烧碱为原料制备了一种多孔镁铝复合氧化物（P—Mg3.1AlO4.6），其比表面积、平均孔径和总孔容分别为206．3m2／g、8．961nm和0．4208cm3／g。研究了这种多孑L材料对水溶液中cr（VI）的吸附性能，在25～45qC时，静态吸附量为82．32～141．7mg／g；当初始浓度100mg／L、流速5mL／min、床层高度10cm和pH=6时，半穿透时间、半穿透吸附量和饱和吸附量分别为406rain、49．28ing／g和51．30Ing／g；拟合参数及误差分析表明，cr（Ⅵ）在P—M敬。AIO4.6上的静态吸附过程符合Freundlich等温方程式和伪二级动力学方程，Yoon·Nelson模型能很好地预测cr（Ⅵ）在P—Mg3.1A104.6上的动态穿透曲线。