活性炭对蒽醌模拟废水的吸附能力研究

使用活性炭作为吸附剂,吸附模拟废水中的1-氨基蒽醌,考察了吸附剂投放比,1-氨基蒽醌初始浓度,反应时间,反应温度对吸附效果的影响。实验发现,当1-氨基蒽醌初始浓度为134 mg/kg,活性炭对其吸附效果最好,而当溶液初始浓度为27 mg/kg,温度为35℃,活性炭的投放比达到0.5 g/L时,30 min后达到吸附平衡并且氨基蒽醌去除率高达86.7%,由此可见,活性炭的吸附能力较高,吸附速度较快,可以作为废水中去除氨基蒽醌的有效吸附剂。     

硅藻土-沸石复合吸附剂去除水体中氮磷的试验研究

本文主要通过静态吸附试验研究了硅藻土-沸石作为复合吸附剂对氮磷废水的处理效率,试验结果表明:与硅藻土或沸石相比,复合吸附剂对氮磷具有较强的吸附能力.吸附试验的最佳条件为:对于该吸附剂去除氨氮,pH=8,初始浓度为40 mg/L,吸附时间为350 min,吸附剂用量20 g/L;对于该吸附剂去除磷,初始浓度为5 mg/L,吸附时间为120 min,吸附剂用量20 g/L.     

炭化污泥吸附剂对Pb~(2+)的吸附试验研究

利用污水处理厂的脱水污泥,采用ZnCl2化学活化热解炭化法制备炭化污泥吸附剂。研究了炭化污泥吸附剂去除水溶液中Pb2+的效果。通过正交试验确定最佳试验参数,试验结果表明,在炭化污泥吸附剂吸附时间为1h,溶液pH值为5.0,炭化污泥吸附剂用量为5g/L时,处理含Pb2+的质量浓度为40mg/L的废水,Pb2+的平均去除率为42.31%,炭化污泥吸附剂的平均吸附容量为2.94mg/g。实际应用中炭化污泥吸附剂可以用于处理低浓度含Pb2+废水,当然为了达到较好的去除效果,炭化污泥吸附剂用量一般不能低于20g/L。     

用13X分子筛去除废水中Pb~(2+)的研究

用13X分子筛作为去除铅离子吸附剂,研究各实验条件下对废水中Pb~(2+)的去除效果。考查了废水的pH、Pb~(2+)起始浓度对去除率的影响,Pb~(2+)起始浓度和吸附时间对吸附容量的影响。优化最佳条件为:控制废水的pH=8,Pb~(2+)浓度为200mg/L,搅拌时间为30min,分子筛投加量在5~6g/L时,13X分子筛对Pb~(2+)的去除率可达到92%左右。研究表明,13X分子筛对Pb~(2+)的吸附机理以离子交换吸附为主,符合Langmuir等温吸附模型。     

褐煤吸附法处理煤气化废水的总氮

研究了褐煤作为吸附剂,处理煤化工气化废水。通过投加量、温度、时间等因素的试验,通过哈希DR3900分光光度计,研究褐煤吸附煤化工气化废水的总氮效果。当褐煤的用量达到400 g/L时,其对总氮的去除率可达到近60%。褐煤作为吸附剂去除废水总氮的方法可作为煤化工废水处理的预处理。     

固液体系中锌离子的动态吸附过程及去除率

在离子浓度50～200 mg/L和蛭石介质浓度50～150 g/L范围内分析测试了固液体系中Zn2 离子的吸附速率.结果表明,蛭石具有较强吸附Zn2 的能力,其吸附速率在初始2h内很高,但随时间的延长逐步降低,并在8 h左右趋于零.溶液起始Zn2 浓度和吸附剂浓度对吸附速率有显著影响,随起始Zn2 浓度增大,吸附达到平衡的时间延长;起始吸附剂浓度越大,吸附平衡时间越短.本文提出的蛭石吸附Zn2 的动态方程在样品检测的浓度范围内具有较高的模拟精确度.中试监测结果表明,人工湿地系统中的蛭石吸附单元可有效去除实验室废水中的锌与其它有毒污染物质.     

城市剩余污泥制备活性炭吸附剂对Ni2+的吸附研究

以城市污水处理厂剩余脱水污泥为原料,采用化学活化热解法制备了污泥活性炭吸附剂,对水溶液中的Ni2+进行去除,确定了最佳实验参数。实验结果表明,吸附时间为1 h、p H为7、吸附剂用量为6 g/L时,对含Ni2+废水(Ni2+质量浓度为50 mg/L)的平均去除率为29.132%,污泥活性炭吸附剂的平均吸附容量为2.428 mg/g。通过单因素实验得出吸附时间为80 min、溶液p H为7时,对溶液中的Ni2+有较好的去除效果。Ni2+在污泥活性炭吸附剂上的吸附比较符合伪二级吸附动力学方程,Langmuir等温方程更适合描述Ni2+在污泥活性炭吸附剂上的吸附行为。     

炭化污泥吸附剂对Pb^2＋的吸附试验研究

利用污水处理厂的脱水污泥,采用ZnCl2化学活化热解炭化法制备炭化污泥吸附剂。研究了炭化污泥吸附剂去除水溶液中Pb^2＋的效果。通过正交试验确定最佳试验参数,试验结果表明,在炭化污泥吸附剂吸附时间为1h,溶液pH值为5．0,炭化污泥吸附剂用量为5g／L时,处理含Pb^2＋的质量浓度为40mg／L的废水,Pb^2＋的平均去除率为42．31％,炭化污泥吸附剂的平均吸附容量为2．94mg／g。实际应用中炭化污泥吸附剂可以用于处理低浓度含Pb^2＋废水,当然为了达到较好的去除效果,炭化污泥吸附剂用量一般不能低于20g／L。     

板栗壳对含油废水中乳化油的吸附行为研究

为了实现农业固体废弃物的资源化利用,以板栗壳作为吸附剂对含乳化油的废水进行了吸附实验研究,探明板栗壳深度处理含油废水的应用潜力。研究了吸附时间、振荡速度、吸附剂颗粒粒径、吸附剂浓度、乳化油初始COD这些因素对板栗壳吸附去除废水中乳化油的去除率及其吸附量的影响。结果表明,板栗壳对乳化油的吸附在20 min时达到吸附平衡,当乳化油初始COD为227.3 mg/L,吸附剂浓度10 g/L,振荡速度200 r/min,吸附剂粒径0.154～0.25 mm时,乳化油去除率和吸附量最大,分别为66.3%和吸附量15.07 mg/g。通过拟一、二阶动力学模型拟合发现板栗壳对乳化油的吸附更符合拟二阶动力学模型,拟合得到的理论平衡吸附量为5.113 5 mg/g,初始吸附速率为3.263 3 mg/（g·min）,化学吸附起主导作用。因此,板栗壳对乳化油的吸附效果较好,有望代替活性炭来深度处理含油废水。     

灭活烟曲霉菌球对砷的吸附

为研究灭活烟曲霉对砷的吸附效果,将烟曲霉菌球经过灭菌(吸附剂Ⅰ)或灭菌后再用FeCl3处理90min(吸附剂Ⅱ),研究了这2种吸附剂在间歇处理过程中对废水中砷的吸附效果。结果表明,2种吸附剂对As3+和As5+均有良好的吸附效果。当废水中砷的质量浓度为0.3576mg/L时,吸附剂I和吸附剂II达到吸附平衡的时间分别为100min和140min。在采用质量浓度为35g/L的生物吸附剂量,达到吸附平衡时,吸附剂I和II对As3+均可完全去除,而对As5+的去除率则分别可达90%和98%。表明灭活烟曲霉菌球可作为砷的有效吸附剂。     

Low cost adsorbents obtained from ash for copper removal

We investigated the utilization of ash and modified ash as a low-cost adsorbent to remove copper ions from aqueous solutions such as wastewater. Batch experiments were conducted to determine the factors affecting adsorption of copper. The influence of pH, adsorbent dose, initial Cu²⁺ concentration, type of adsorbent and contact time on the adsorption capacity of Cu²⁺ from aqueous solution by the batch adsorption technique using ash and modified ash as a low-cost adsorbent were investigated. The optimum pH required for maximum adsorption was found to be 5. The results from the sorption process showed that the maximum adsorption rate was obtained at 300 mg/L when a different dosage of fly ash was added into the solution, and it can be concluded that decreasing the initial concentration of copper ion is beneficial to the adsorption capacity of the adsorbent. With the increase of pH value, the removal rate increased. When the pH was 5, the removal rate reached the maximum of over 99%. When initial copper content was 300 mg/L and the pH value was 5, the adsorption capacity of the zeolite Z 4 sample reached 27.904 mg/g. The main removal mechanisms were assumed to be the adsorption at the surface of the fly ash together with the precipitation from the solution. The adsorption equilibrium was achieved at pH 5 between 1 and 4 hours in function of type of adsorbent. A dose of 1: 25 g/mL of adsorbent was sufficient for the optimum removal of copper ions. For all synthesized adsorbents the predominant mechanism can be described by pseudo-second order kinetics.     

Adsorptive removal of fluoride from water samples using <Emphasis Type="Italic">Azospirillum</Emphasis> biofertilizer and lignite

The present study involves a comparison of Azospirillum biofertilizer and lignite for removal of fluoride from aqueous solution. Batch experiments were performed to remove fluoride by the use of Azospirillum biofertilizer and lignite. Fluoride adsorption capacity was found by varying different parameters such as adsorbent dose, pH, initial concentration, temperature and contact time. The adsorption capacity for fluoride by using Azospirillum biofertilizer was 0.456 mg/g and for lignite 0.16 mg/g. Pseudo-second-order kinetic model best fit the experimental data. Field water samples were tested for fluoride removal by Azospirillum biofertilizer and lignite. The fluoride concentration was reduced to the permissible limit.     

Adsorption behavior of fluoride ions using a titanium hydroxide-derived adsorbent

The removal behavior of fluoride ions was examined in aqueous sodium fluoride solutions using a titanium hydroxide-derived adsorbent. The adsorbent was prepared from titanium oxysulfate (TiOSO₄·xH₂O) solution, and was characterized by X-ray diffraction, scanning electron microscopy, thermogravimetry-differential thermal analysis, Fourier transform infrared spectrum and specific surface area. Batchwise adsorption test of prepared adsorbent was carried out in aqueous sodium fluoride solutions and real wastewater containing fluoride ion. The absorbent was the amorphous material, which had different morphology to the raw material, titanium oxysulfate, and the specific surface area of the adsorbent (96.8 m²/g) was 200 times higher than that of raw material (0.5 m²/g). Adsorption of fluoride on the adsorbent was saturated within 30 min in the solution with 200 mg/L of fluoride ions, together with increasing pH of the solution, due to ion exchange between fluoride ions in the solution and hydroxide ions in the adsorbent. Fluoride ions were adsorbed even in at a low fluoride concentration of 5 mg/L; and were selectively adsorbed in the solution containing a high concentration of chloride, nitrate and sulfate ions. The adsorbent can remove fluoride below permitted level (< 0.8 mg/L) from real wastewaters containing various substances. The maximum adsorption of fluoride on the adsorbent could be obtained in the solution at about pH 3. After fluoride adsorption, fluoride ions were easily desorbed using a high pH solution, completely regenerating for further removal process at acidic pH. The capacity for fluoride ion adsorption was almost unchanged three times after repeat adsorption and desorption. The equilibrium adsorption capacity of the adsorbent used for fluoride ion at pH 3 was measured, extrapolated using Langmuir and Freundlich isotherm models, and experimental data are found to fit Freundlich than Langmuir. The prepared adsorbent is expected to be a new inorganic ion exchanger for the removal and recovery of fluoride ions from wastewater.     

Quaternized Three-Dimensionally Ordered Macroporous Cross-Linked Polystyrene and its Adsorption Character toward Salicylic Acid in Aqueous Solution

Three-dimensionally ordered macroporous cross-linked polystyrene loaded with quaternary ammonium groups (3DOM CLPS-QA) was prepared for using as a novel adsorbent. The performance of 3DOM adsorbent was evaluated by adsorbing salicylic acid (SA) in aqueous solution. Adsorption isotherm and kinetics were investigated under different temperatures (293 K, 303 K, 313 K). The rising temperature led to a significant increase in the adsorption capacity towards SA, and 3DOM CLPS-QA exhibited a high adsorption capacity (317.86 mg/g when the initial concentration of SA was 500 mg/L at 303 K). Moreover, the effect of solution pH on adsorption indicated that the charge interaction was the dominating driving force for the adsorption of SA onto 3DOM CLPS-QA from the aqueous solution. The 3DOM adsorbent was also reusable and could be regenerated by 0.1 M hydrochloric acid solution. After reusing for six times, the adsorption capacity still maintained about 80% of the original capability.     

Removal of methylene blue dye from aqueous solutions by a new chitosan/zeolite composite from shrimp waste: Kinetic and equilibrium study

The adsorption of methylene blue dye (MBD) from aqueous solutions was investigated using a new composite made up of shrimp waste chitosan and zeolite as adsorbent. Response surface methodology (RSM) was used to optimize the effects of process variables, such as contact time, pH, adsorbent dose and initial MBD concentration on dye removal. The results showed that optimum conditions for removal of MBD were adsorbent dose of 2.5 g/L and pH of 9.0, and initial MBD concentration of 43.75 mg/L and contact time of 138.65 min. The initial concentration of dye had the greatest influence on MBD adsorption among other variables. The experimental data were well fitted by the pseudo-second order kinetic model, while the Freundlich isotherm model indicated a good ability for describing equilibrium data. According to this isotherm model, maximum adsorption capacity of the composite was 24.5 mg/g. Desorption studies showed that the desorption process is favored at low pH under acidic conditions.     

水滑石焙烧产物对阴离子染料靛蓝胭脂红的吸附特性

碳酸根型水滑石焙烧产物对阴离子染料具有特异的吸附性能。该研究考察了两种具有不同镁铝摩尔比的镁铝复合氧化物对靛蓝胭脂红的吸附性能,并探讨了焙烧温度、投加量、初始染料浓度、溶液初始pH以及共存阴离子这几个因素的影响。结果表明经过500℃焙烧处理后的水滑石对染料的去除效果最好,去除率高达95%,平衡吸附量高达811.5 mg/g（1.74 mmol/g）;且吸附过程不受初始溶液pH和共存阴离子的影响。水滑石焙烧产物直接用于印染废水处理,脱色率达68%~84%。     

Ultrasound Irradiation Facilitated Adsorption of MTBE from Aqueous Solution using Exfoliated Graphite

Water pollution due to the fuel additive methyl tert‐butyl ether (MTBE), which is a suspected carcinogen, is often observed in surface and ground water. The removal of MTBE from aqueous solution at a concentration of 0.00143 g/mL by using exfoliated graphite (EG) as a novel adsorbent is reported. Experiments are carried out in batch mode and the effects of several factors on the removal of MTBE are evaluated. In addition, the influence of ultrasound irradiation on MTBE adsorption is investigated. The results show that an efficient removal of MTBE from aqueous solution could be achieved by implementing an ultrasound facilitated adsorption process using EG. A maximum removal efficiency of 97 % is achieved for MTBE in controlled conditions and it is found that applying ultrasound has a significant positive effect on the removal of MTBE from aqueous solutions.     

Preparation and characterization of a novel nanocomposite of clinoptilolite/maghemite/chitosan/urea for manganese removal from aqueous solution

Synthesis of a new magnetic nanocomposite of Clinoptilolite/Maghemite/Chitosan/Urea has been carried out to introduce an adsorbent to remove manganese as a toxic heavy metal from aqueous solution. Clinoptilolite zeolite became magnetic using the maghemite nanoparticles, then coated using chitosan as a biodegradable and non-toxic polymer, and finally functionalized by urea to increase the adsorption capacity. For characterization of the nanocomposite, the X-Ray diffraction, IR spectroscopy, vibrating sample magnetometery, and scanning electron microscopy were used. The effects of temperature, contact time, initial metal concentration, solution pH and adsorbent dose on the manganese removal capacity were evaluated. The kinetics of adsorption by the pseudo-first-order, pseudo-second-order, and Elovich kinetic models was studied and the results suggested the compliance of pseudo-second-order kinetic model with the kinetic data. The maximum adsorption capacity of manganese under the optimum condition of pH=2.13, the adsorbent amount of 0.02 g, initial solution concentration of 46.00 mg/L with response surface methodology, equaled 16.30 mg/g. The Langmuir, Freundlich, Temkin and Dobinin-Rudoshkovich adsorption isotherm models were investigated and Langmuir best fit the isotherm data. In the study of the thermodynamic results, negative Gibbs free energy represents the spontaneous nature of manganese removal process.     

Removal of Fluoride from Aqueous Solution by CaO Nanoparticles

Abstract

Colloidal particles of CaO were synthesized by the sol-gel method. The particle morphology was characterized by FT-IR, TGA, DTA, and TEM analysis. The ability of the CaO nanoparticles for removal of fluoride from aqueous solution through adsorption has been investigated. All the experiments were carried out by batch mode. The effect of various parameters viz. contact time, pH effect (pH 2–10), adsorbent dose (0.01–0.1 g/100 ml), initial fluoride concentration (10–100 mg/l) and competitive ions has been investigated to determine the adsorption capacity of CaO nanoparticles. Almost complete removal (98%) of fluoride was obtained within 30 minutes at an optimum adsorbent dose of 0.6 g/L for initial fluoride concentration of 100 mg/L. The adsorption isotherm was also studied to find the nature of adsorbate-adsorbent interaction.     

聚丙烯酸复合铝改性膨润土制备及其对Cr(VI)的吸附

为改善膨润土对Cr(VI)的吸附性能,用铝、丙烯酸聚合及十六烷基三甲基溴化铵改性合成聚丙烯酸复合铝改性膨润土。采用X射线衍射、红外光谱和扫描电子显微镜对天然膨润土和改性膨润土进行表征。结果表明,在25℃、溶液pH=5~6时,0.5 g吸附剂对200 mL浓度为20 mg/L Cr(VI)的平衡吸附量为1.996 mg/g,平衡吸附时间为130 min,且固液分离容易。吸附过程较好地符合Lagergren二级吸附动力学方程和Freundlich等温吸附方程,颗粒状吸附剂对Cr(VI)的吸附以络合吸附为主。