CPB与HDTMA改性沸石处理含Cr(Ⅵ)废水性能比较

分别采用溴代十六烷基吡啶(CPB)与十六烷基三甲基溴化铵(HDTMA)改性的天然沸石处理含Cr(Ⅵ)废水.对其性能与影响因素进行了比较,实验结果表明:CPB改性沸石的性能优于HDTMA改性沸石.CPB改性沸石的最佳改性浓度为1.0%,最佳改性温度为30℃,吸附时间为20min,吸附容量为HDTMA改性沸石的4倍.     

锰改性活性炭对Cr(Ⅵ)的吸附研究

Cr(Ⅵ)是一种高毒性重金属.为了探究炭质材料对水中六价铬的吸附行为,首次尝试用不同浓度的锰离子溶液对颗粒活性炭进行改性,研究了包括pH、温度、投加量和Cr(Ⅵ)初始浓度对原活性炭和改性活性炭的对比实验.结果表明在相同的条件下锰离子改性可以增加活性炭对Cr(Ⅵ)的吸附容量,溶液pH、温度、投加量和初始浓度对CKⅥ)的去除率有很大影响.活性炭对Cr(Ⅵ)的吸附等温线与Langrmuir模型有更好的线性相关性.     

改性粘土预处理垃圾渗滤液中氨氮的吸附热力学和动力学研究

采用十六烷基三甲基溴化铵(HDTMA)对粘土进行改性,通过X射线衍射、红外光谱、热分析技术对改性粘土进行表征,分析作用机理;并将改性粘土用于垃圾渗滤液中氨氮的处理,对处理过程的吸附热力学和动力学性能进行研究。研究表明:粘土经过改性后,改性粘土的层间间距增大了0.754 nm;在303.15 K,313.15 K,333.15 K不同温度下,粘土吸附渗滤液中氨氮的平衡的时间为50 min左右,改性后的粘土吸附效果比原土提高了大约2~3倍;改性粘土对氨氮的吸附符合Langmuir等温吸附模型和Freundlich等温吸附模型;吸附过程标准摩尔吉布斯自由能△G~θ在-0.127 kJ/mol^-0.080 kJ/mol范围内,标准摩尔焓变△H~θ<0,吸附反应过程均属自发的放热过程;吸附动力学数据符合准二级动力学方程和粒子内扩散方程。     

热解含油污泥制备吸附材料浅析

介绍了含油污泥热解技术及热解实验方法,提出热解产生的残渣进行适当处理可成为具有吸附性的材料。进行了含油污泥热解正交实验,得出影响最大的因素分别是热解温度、热解时间、升温速率,并得出最佳的热解温度、热解时间、升温速率等。分析了含油污泥热解的机理,探讨了热解含油污泥制备吸附材料的活化改性,并在此基础上对所制备吸附材料的脱硫性和除油性进行了研究。     

改性玉米秸秆吸附去除废水中四环素的研究

应用平衡吸附法,研究了不同投加量（改性玉米秸秆）、温度及pH条件下,改性玉米秸秆对水体中四环素的吸附作用,并利用等温曲线及吸附动力学方程对试验结果进行了拟合。结果表明：在吸附剂用量0．4g,温度30℃,振荡时间30min,pH值7的条件下,对水体中四环素浓度为50．136mg／L的吸附率可达93．4％。四环素废水吸附均符合Langmuir及Freundlich等温模式。但Langmuir方程拟合得较好,Elovich方程能更好地拟舍改性玉米秸秆对水体中四环素的吸附动力学曲线。     

燃煤电厂烟道喷射吸附剂脱Hg技术研究

简介了活性炭吸附脱Hg、改性活性炭吸附脱Hg、飞灰吸附脱Hg和改性飞灰吸附脱Hg四类技术,指出改性飞灰吸附脱Hg技术是当前技术经济性最好的吸附脱Hg技术。     

改性介孔二氧化硅对硫化氢的吸附研究

以均匀沉淀法合成金属氧化物改性介孔二氧化硅,并通过气体穿透实验考察了其吸附H_2S气体的性能。实验表明,CuO负载量为40%(质量分数)、450℃下焙烧4h制备的改性二氧化硅具有最佳的吸附性能,其穿透时间为247.3min,穿透吸附量达50.5mg/g。     

热改性农作物废料对海洋溢油吸附研究

以秸秆和玉米叶为吸油材料,分别经50,100,150,200℃热处理后,进行模拟溢油吸附实验,确定不同温度下热改性材料的吸油能力。实验结果表明:热改性后的农作物材料对原油的饱和吸附时间较短,当温度低于100℃时,热改性后材料对原油的饱和吸附时间为5 min,随着温度的增加,饱和吸附时间减小,在温度达到150℃和200℃时,材料对原油的饱和吸附时间缩短到4 min和3 min。秸秆对原油的平衡吸附量随着温度的升高而增加,但当热处理温度达到200℃时,其对原油的平衡吸附量反而下降。不同温度热改性后的玉米叶对原油的平衡吸附量基本一致。     

改性茶叶对工业废水中F-的吸附性能

采用甲醛和三氯化铁改性茶叶制成茶叶质铁吸附剂,研究其对工业废水中F-的吸附性能.探讨不同茶叶质铁吸附剂投加量、F-初始浓度、pH、温度对吸附率的影响,确定最佳吸附条件;采用SEM、BJH、XRD、红外分析等研究改性后茶叶质铁吸附剂的基本物理化学特性;最后对茶叶质铁吸附剂的洗脱与再生性及吸附机理进行了探讨.结果表明:当茶...     

改性钛管基复合吸附剂及其在油田伴生气中CO_2脱除的应用

通过湿式浸渍法制备了胺改性复合吸附剂用于油田伴生气中的CO_2捕集回收。采用物理吸附仪(BET-BJH)、热重分析仪(TG)考察了复合吸附剂的微观结构和热稳定性;通过等温吸附曲线研究了胺改性钛管对CO_2的吸附特性和对CH4/CO_2的吸附选择性。实验结果表明,胺改性复合吸附剂适用于150℃下的操作环境,在75℃时对CO_2的吸附容量可高达110mg/g;其对CO_2的吸附符合准二级动力学模型。40PEI/HTO对CO_2亲和性强,是分离CO_2/CH4的优异吸附剂。     

小叶榕落叶改性条件优化及其处理含Cu~(2+)废水动力学研究

以废弃的小叶榕落叶作为吸附剂,通过正交试验选择制备改性小叶榕落叶的最佳条件,结果表明:当硝酸浓度为10moL/L,干燥温度为120℃和氢氧化钠浓度为1moL/L时,改性后的小叶榕落叶的活性最强,对废水中Cu2+的吸附率最高。利用改性后的小叶榕落叶进行了吸附去除水中Cu2+的研究,得出当pH为5.7,铜的最大吸附容量Qmax=0.59mg(Cu)/g(改性落叶)。并通过非线性回归,构建了影响因素同吸附率之间的数学模型和落叶吸附的动力学模型。     

Adsorption of cadmium on carbonaceous adsorbents developed from used tire rubber

Carbonaceous adsorbents (CAs) are developed from used tire rubber (UTR) and tested as adsorbents of Cd(2+) in aqueous solution. In the preparation of the CAs, UTR was treated thermally at 400-900 °C for 2 h in N(2) and at 850 °C for 2 h in steam. Concentrated NaOH, HCl, H(2)SO(4), HNO(3) and H(2)O(2) solutions were also used. UTR and H900 (i.e. UTR pyrolyzed at 900 °C) were treated with O(3) at 25 °C for 1 h and with air at 250 °C for 1 and 24 h. CAs were characterized texturally by N(2) adsorption at -196 °C, mercury porosimetry, and density measurements. The surface groups were analyzed by FT-IR spectroscopy. Using the batch method, the adsorption process of Cd(2+) was studied mainly from the kinetic standpoint at various pH values of the adsorptive solution. Significant porosity developments are achieved only when UTR is heat-treated, in particular in steam. However, the variety and concentration of surface groups are low in CAs. This is so even for CAs prepared using oxidizing agents as strong as O(3) and H(2)O(2), which has been associated with a lack of available or accessible surface active sites for oxidation in UTR and H900, respectively. Thermal and thermal-chemical treatments are usually more effective than chemical treatments to increase the adsorption of Cd(2+) in aqueous solution. The adsorption process of Cd(2+) is first fast and then much slower. Adsorption-time data fit better to a pseudo-second order kinetic equation than to a pseudo-first order kinetic equation. The extent to which the adsorption process occurs is strongly dependent on the pH of the Cd(2+) solution, being larger at pH 4.6 or 7.0 according to the adsorbent.     

电化学反应器吸附去除氟离子的研究

采用改性活性炭粉末对用纯净水加氟化钠配制而成的含氟水溶液进行动态电吸附去除实验.研究不同电压、电吸附时间,以及Cl-和SO2-4对氟离子去除的影响,并探讨吸附动力学和吸附方程.实验结果表明:活性炭对氟离子的吸附等温方程符合Freundlich方程,吸附动力学符合一级动力学方程;活性炭对氟离子去除与所施加的电位、吸附时间等因素有关,施加的电位越大,去除效果越好;随着吸附去除时间的延长,氟离子浓度下降趋缓;Cl-对氟离子去除影响很小,而SO2-4对氟离子去除有显著的不利影响.     

改性沸石对水体中硝酸盐的吸附机理及其残渣的资源化利用

利用HDTMA改性沸石制成吸附剂,研究对水体中硝酸盐的吸附能力和机理及吸附剂残渣的资源化应用前景。结果表明:HDTMA改性沸石可增强其对硝酸盐的吸附能力。通过红外光谱和差热分析它的吸附机理,表明:改性沸石HZ4吸附有十六烷基三甲基溴化铵(HDTMA)分子;吸附剂残渣NHZ4吸附有十六烷基三甲基溴化铵(HDTMA)分子和硝酸盐。盆栽实验结果表明:吸附剂残渣NHZ4能提高玉米生物量,最大增幅为30.4%。     

Adsorption of carbon dioxide using impregnated activated carbon promoted by Zinc

The effect of impregnation of activated carbon with Cr₂O and Fe₂O₃ and promotion by Zn²⁺ on its adsorptive properties of carbon dioxide was studied using a volumetric adsorption apparatus at ambient temperature and low pressures. Slurry and solution impregnation methods were used to compare CO₂ capture capacity of the impregnated activated carbon promoted by Zinc. The obtained adsorption isotherms showed that amount of CO₂ adsorbed on the samples impregnated by Cr₂O was increased about 20% in compare to raw activated carbon. The results also showed that Fe₂O₃ was not an effective impregnating species for activated carbon modification. Moreover slurry impregnation method showed higher CO₂ adsorption capacity in comparison with solution impregnation method. Samples prepared by co-impregnation of two metal species showed more adsorption capacity than samples impregnated by just one metal species individually. Washing the impregnated samples by metal oxide resulted in 15% increase in CO₂ adsorption capacities of activated carbons which can be attributed to the metal oxides removal covering the adsorption surface. Decreasing impregnation temperature from 95 to 25 °C in solution method showed a significant increase in CO₂ adsorption capacity. Sips equation was found a suitable model fitting to the adsorption data in the range studied.     

Fenton试剂与改性凹凸棒石联合处理微污染水中苯酚的实验研究

研究了Fenton试剂联合聚二甲基二烯丙基氯化铵（PDMDAAC）改性凹凸棒石对模拟微污染水中苯酚的去除效果。考察了pH值、反应时间、投加量、温度等因素对苯酚去除效果的影响。结果表明：先采用Fenton试剂氧化再用改性凹凸棒石吸附对微污染水中苯酚具有较好的去除效果,在pH=9、温度为25℃、改性凹凸棒石投加量为5g／L、吸附时间20min的条件下,苯酚去除率达98．2％。     

A comparative study for the sorption of Cd(II) by K-feldspar and sepiolite as soil components, and the recovery of Cd(II) using rhamnolipid biosurfactant

This study investigated the sorption characteristics and recovery of selected heavy metal Cd(II) from K-feldspar and sepiolite, representative soil components, using rhamnolipid biosurfactant. Although the proposed technique was classified as a soil bioremediation process, it can also be applied to treatment of waste waters containing Cd(II) ions with minor modifications. The effect of initial Cd(II) concentration on sorption capacity was characterized by determining the sorption isotherms. Of the four models examined, the Freundlich model showed the best fit for the sorption of Cd(II) on K-feldspar, whereas the Langmuir-model was used successfully to characterize the sorption of Cd(II) on sepiolite. Although a high Cd(II) uptake of 7.49 mmol/kg by K-feldspar was obtained, sepiolite was a superior Cd(II) accumulater, with a maximum Cd(II) uptake of 24.66 mmol Cd(II)/kg. The presence of Cd(II) in the sepiolite or K-feldspar prior to addition of the rhamnolipid generally resulted in less rhamnolipid sorption to sepiolite or K-feldspar. The maximum Cd(II) desorption efficiency by rhamnolipid from K-feldspar was substantially higher than that of sepiolite and determined to be 96% of the sorbed Cd(II), whereas only 10.1% of the sorbed Cd(II) from sepiolite was recovered by rhamnolipid solution.     

Cellulose-based anion exchanger with tertiary amine functionality for the extraction of arsenic(V) from aqueous media

A novel cellulose-based anion exchanger (Cell-AE) with tertiary amine functionality was synthesized by graft polymerization reaction of cellulose and glycidyl methacrylate using N,N′-methylene-bis-acrylamide as a crosslinker and benzoyl peroxide as an initiator, followed by dimethylamine (amination) and acid (HCl) treatment. The chemical modification was confirmed by infrared spectroscopy and CHN analysis. The anion exchanger was used in batch processes to study AS(V) adsorption in solutions. The operating variables studied were pH, contact time, initial As(V) concentration, sorbent mass, and ionic strength. The process was affected by solution pH with an optimum adsorption occurring at pH 6.0. Adsorption equilibrium was achieved within 1 h. Increasing ionic strength of solution negatively affected the arsenic uptake. The adsorption process performed more than 99.0% of As(V) removal from an initial concentration of 25.0 mg/L. The process of adsorption followed pseudo-second-order kinetics. The adsorption equilibrium isotherm data were analyzed using the Langmuir, Freundlich, Redlich–Peterson and Langmuir–Freundlich equations. The Langmuir–Freundlich isotherm described the adsorption data over the concentration range 25–400 mg/L. The adsorption mechanism appears to be a ligand-exchange process. A simulated groundwater sample was treated with Cell-AE to demonstrate its efficiency in removing As(V). The adsorbed As(V) ions were desorbed effectively by a 0.1 M NaOH solution.     

Removal of phosphorus from aqueous solutions using chemically modified sawdust of Aleppo pine (<Emphasis Type="Italic">Pinus halepensis Miller</Emphasis>): kinetics and isotherm studies

In the present study, chemically modified Aleppo pine (Pinus halepensis Miller) sawdust was used for the removal of phosphate from water. Biosorbent preparation process included size fractionation, extraction for surface activation, acid prehydrolysis, and treatment with urea. Sorption of phosphate ions onto biosorbent was studied using the batch technique. The effect of different parameters such as contact time, adsorbate concentration, and temperature was investigated. The adsorption kinetics data were best described by the pseudo-second-order rate equation, and equilibrium was achieved after 40 and 80 min for modified and unmodified sawdust, respectively. The Langmuir and Freundlich equations for describing adsorption equilibrium were applied to data. The constants and correlation coefficients of these isotherm models were calculated and compared. The adsorption isotherms obey the Freundlich equation. The thermodynamic parameters like free energy, enthalpy, and entropy changes for the adsorption of phosphate ions have been evaluated, and it has been found that the reaction was spontaneous and endothermic in nature. The low value of activated energy of adsorption, 3.088–3.540 kJ mol⁻¹, indicates that the phosphate ions are easily adsorbed on the sawdust. Results suggest that the prepared chemically modified Aleppo pine sawdust has potential in remediation of contaminated waters by phosphate.     

Adsorption of carbon dioxide on alkali-modified zeolite 13X adsorbents

Shaped zeolite 13X adsorbent with kaolin as binder was hydrothermally modified in sodium hydroxide solution to improve its adsorption performance. The characterization of the product by XRD, N₂ adsorption–desorption and water vapour adsorption displayed that kaolin component in zeolite adsorbent can be converted into zeolite during the alkali treatment, resulting in the modified adsorbent consisting entirely of effectual adsorption composition. Compared with the unmodified adsorbent, the modified adsorbent exhibited higher adsorption capacity and uptake rate for carbon dioxide, because of the increase of effective adsorption surface and the decrease of diffusion resistance owing to conversion of kaolin binder into zeolite. The model parameters of isotherms and the isosteric heats calculated by the Clausius–Clapeyron equation for CO₂ adsorption showed the stronger interaction of adsorbate–adsorbent and the higher degree of heterogeneity of adsorption centers in modified than unmodified adsorbents.