Dye removal from wastewater using the adsorbent developed from sewage sludge

Introduction Adsorptionisrelevantinenvironmentalpollutionandprotectionwithreferencetowaterandwastewatertreatment(Bowen,1992).Toxicmaterials,hazardousionsanddyes fromindustrialeffluentsbythewayofadsorptionareofgreatsignificantinconnectionwithenvironmentala…     

TiO2/Ag modified penta-bismuth hepta-oxide nitrate and its adsorption performance for azo dye removal

A modified hydrophilic penta-bismuth hepta-oxide nitrate (Bi₅O₇NO₃) surface was synthesized via a precipitation method using TiO₂ and Ag as modified agents. The synthesized product was characterized by different analytical techniques. The removal efficiency was evaluated using mono-and di-sulphonated azo dyes as model pollutants. Different kinetic, isotherm and diffusion models were chosen to describe the adsorption process. X-ray photoelectron spectroscopy (XPS) results revealed no noticeable differences in the chemical states of modified adsorbent when compared to pure Bi₅O₇NO₃;however, the presence of hydrophilic centres such as TiO₂ and Ag developed positively charged surface groups and improved its adsorption performance to a wide range of azo dyes. Dyes removal was found to be a function of adsorbent dosage, initial dye concentration, solution pH and temperature. The reduction of Langmuir 1,2-mixed order kinetics to the second or first-order kinetics could be successfully used to describe the adsorption of dyes onto the modified adsorbent. Mass transfer can be described by intra-particle diffusion at a certain stage, but it was not the rate limiting step that controlled the adsorption process. Homogenous behavior of adsorbent surface can be explored by applying Langmuir isotherm to fit the adsorption data.     

粉煤灰对阴离子水溶性混合染料的吸附动力学

以燃煤废弃物粉煤灰作为吸附剂,对活性红23与活性蓝4、活性黄4、酸性黑1、酸性蓝193的混合染料溶液进行吸附性能研究.结果表明,在不同的混合体系中,活性红23的脱色率基本保持在60%~70%;体系中酸性染料的脱色率均超过90%;活性蓝4的脱色率高达85%;活性黄4的脱色率仅为50%.准二级吸附动力学能够更好地描述粉煤灰对水溶性混合染料的吸附过程.染料在溶液中的外扩散系数均为10-4cm·s-1数量级,染料在粉煤灰颗粒的内扩散系数为10-8cm2·s-1数量级.根据BN数,水溶性染料在粉煤灰上的竞争吸附是外扩散控制的吸附过程.     

净水污泥与粉末活性炭复合制备吸附剂去除氨氮研究

将净水污泥与粉末活性炭复合制备吸附剂,用于去除水中的氨氮。研究了净水污泥与粉末活性炭的最佳复合比例及煅烧温度,并采用EDX、SEM、XRD、FTIR、BET对吸附剂进行表征。考察了吸附时间、溶液初始pH、吸附剂投加量、氨氮初始浓度对氨氮吸附效果的影响。结果表明:复合吸附剂的吸附性能优于原泥,当吸附时间为5 h,pH为9时氨氮去除效果最佳。对实验结果进行吸附等温线及吸附动力学模型拟合,发现复合吸附剂对氨氮的吸附过程符合Langmuir等温吸附模型及二级动力学方程。     

笼芯陶黑碳微珠去除模拟废水中铬

将笼芯陶黑碳微珠用于水溶液中铬的吸附去除,探讨了溶液初始pH、初始浓度、吸附温度、吸附时间、竹炭添加量对铬去除的影响,分析了铬去除的等温过程、动力学和热力学。结果表明:较低的溶液初始pH、较高的吸附温度、较长的吸附时间和较大的笼芯陶黑碳微珠添加量有利于铬的吸附去除;铬的去除更符合D-R模型和准二级动力学模型,其饱和吸附量可达到30.62 mg/g;铬去除过程的控速步骤为液膜扩散和颗粒内扩散联合控制,但以液膜扩散为主导;笼芯陶黑碳微珠对铬的去除是自发的、吸热的、以化学吸附为主的过程。     

Adsorption characteristics of humic acid-immobilized amine modified polyacrylamide/bentonite composite for cationic dyes in aqueous solutions

Humic acid-immobilized amine modified polyacrylamide/bentonite composite (HA-Am-PAA-B) was prepared and used as an adsorbent for the adsorption of cationic dyes (Malachite Green (MG), Methylene Blue (MB) and Crystal Violet (CV)) from aqueous solutions. The polyacrylamide/bentonite composite (PAA-B) was prepared by intercalative polymerization of acrylamide with Nabentonite in the presence of N,N0-methylenebisacrylamide as a crosslinking agent and hexamethylenediammine as propagater. PAA-B was subsequently treated with ethylenediammine to increase its loading capacity for HA. The surface characterizations of the adsorbent were investigated. The adsorbent behaved like a cation exchanger and more than 99.0% removal of dyes was detected at pH range 6.0–8.0. The capacity of HA-Am-PAA-B was found to decrease in the following order: MG > MB > CV. The kinetic and isotherm data were interpreted by pseudo-second order rate equation and Freundlich isotherm model, respectively. Experiments were carried out using binary solute systems to assess the competitive adsorption phenomenon. The experimental isotherm data for each binary solute combination of MG, MB and CV were analyzed using Sheindrof-Rebhun-Sheintuch (SRS) (multicomponent Freundlich type) equation.     

活性炭对含铜制药废水的吸附特性

以粉末活性炭为吸附剂,采用批式试验,研究静态吸附对黄连素脱铜废水中Cu2+的去除效果,分析了吸附剂投加量(5～50 g/L),pH(1.0～5.0)和接触时间(20～600 min)对吸附效果的影响. 当pH为2.4,吸附剂投加量为30 g/L时,反应300 min即可达到吸附平衡状态. 通过对吸附动力学和吸附等温线的模型分析发现,二级吸附动力学模型能够更好地描述试验结果,对吸附平衡数据的拟合采用Langmuir吸附等温线优于采用Freundlich吸附等温线.      

GA-g-PAMPS/AA/ST凝胶的制备及对亚甲基蓝吸附性能

采用微波辐射技术,通过接枝共聚反应制备了阿拉伯胶（GA）-g-2-丙烯酰胺-2-甲基丙磺酸（AMPS）/丙烯酸（AA）/海泡石黏土（ST）（GA-g-PAMPS/AA/ST）复合水凝胶,利用FTIR、XRD、SEM对复合水凝胶进行了表征,研究了水凝胶对水溶液中亚甲基蓝（MB）染料的吸附性能.结果显示：GA、ST和AA与AMPS发生了接枝共聚反应,形成具有均匀三维网络结构的复合水凝胶.0.025g水凝胶可以使体积为50mL、pH值为6.4、浓度为600mg/L的MB溶液的吸附量和吸附率分别达1146mg/g和95.5%,水凝胶具有较好的重复利用性能.Freundlich等温模型和准二级动力学模型能更好地描述吸附过程.热力学研究表明水凝胶对亚甲基蓝吸附是自发、吸热和不可逆的过程.该水凝胶可用作阳离子染料和阳离子型污染物的潜在候选生物质吸附剂.     

粉煤灰对混合染料的吸附性能研究

以燃煤废弃物粉煤灰作为吸附剂,对活性红23和分散蓝56混合染料溶液进行吸附性能研究.实验结果表明:粉煤灰优先吸附离子型的活性染料,混合溶液中对活性红23的吸附能够在30 min达到平衡,而对分散蓝56的吸附则需要150 min才能够达到平衡,吸附动力学符合准二级吸附模型.在弱酸性环境中粉煤灰对分散染料的脱色高于碱性环境...     

GA-g-PAMPS/AA/ST凝胶的制备及对亚甲基蓝吸附性能

采用微波辐射技术,通过接枝共聚反应制备了阿拉伯胶（GA）-g-2-丙烯酰胺-2-甲基丙磺酸（AMPS）/丙烯酸（AA）/海泡石黏土（ST）（GA-g-PAMPS/AA/ST）复合水凝胶,利用FTIR、XRD、SEM对复合水凝胶进行了表征,研究了水凝胶对水溶液中亚甲基蓝（MB）染料的吸附性能.结果显示：GA、ST和AA与AMPS发生了接枝共聚反应,形成具有均匀三维网络结构的复合水凝胶.0.025g水凝胶可以使体积为50mL、pH值为6.4、浓度为600mg/L的MB溶液的吸附量和吸附率分别达1146mg/g和95.5%,水凝胶具有较好的重复利用性能.Freundlich等温模型和准二级动力学模型能更好地描述吸附过程.热力学研究表明水凝胶对亚甲基蓝吸附是自发、吸热和不可逆的过程.该水凝胶可用作阳离子染料和阳离子型污染物的潜在候选生物质吸附剂.     

利用新型稀土铈铁复合吸附剂去除水体腐殖质的研究

研究了稀土铈铁复合材料(CFA)对水体中黄腐酸(FA)的去除效能和作用机制.结果表明:CFA在平衡pH3.0～6.5的范围内对FA的去除效果较好,吸附速度快,120min即达到平衡.水体中FA与砷酸根在CFA上有很强的竞争作用,当FA加入量为5mg/L～10mg/L时,砷的饱和吸附量Q_o即丧失40%～50%,表明两者作用于材料相同的活性位点.吸附前后的红外谱图(FTIR)揭示了CFA表面羟基在FA去除中起着重要作用.通过Zeta电位的测定得出材料的等电点为5.6,因而pH偏酸性的条件有利于FA的去除.     

干活性污泥吸附水中染料的试验研究

以城市污水处理厂干活性污泥为吸附剂对染料直接深棕M、酸性媒介棕RH进行了吸附研究,结果表明,吸附过程能很好地用二级速率表达式表示,同时也可用Lagergren一级速率方程描述。其一级吸附速率常数k1分别为0.0204min-1和0.0068min-1,二级吸附速率常数k2分别为0.00592和0.00589gmg-1min-1。两者的吸附特性不同,其吸附等温线前者符合Freundlich方程,后者既符合Freundlich方程也符合Langmuir方程。吸附平衡时间、去除率亦不同,前者明显大于后者,达到吸附平衡的时间分别为120min和240min。两种染料的正辛醇/水分配系数logP计算数值分别为4.65和-0.22,这一顺序与两种染料在干污泥上的吸附行为相符。     

Synthesis of malachite@clay nanocomposite for rapid scavenging of cationic and anionic dyes from synthetic wastewater

Synthesis of malachite@clay nanocomposite was successfully carried out for the removal of cationic (Methylene Blue, MB) and anionic dyes (Congo Red, CR) from synthetic wastewater. Nanocomposite was characterized by TEM, SEM, FT-IR, EDS analysis and zeta potential. TEM analysis indicated that the particle diameter of nanocomposite was in the range of 14 to 23 nm. Various important parameters viz. contact time, concentration of dyes, nanocomposite dosage, temperature and solution pH were optimized to achieve maximum adsorption capacity. In the case of MB, removal decreased from 99.82% to 93.67% while for CR, removal decreased from 88.55% to 75.69% on increasing dye concentration from 100 to 450 mg/L. pH study confirmed the higher removal of CR in acidic range while MB removal was higher in alkaline range. Kinetic study revealed the applicability of pseudo-second-order model for the adsorption of both dyes. Negative values of ΔG⁰ for both systems suggested the feasibility of dye removal and support for spontaneous adsorption of CR and MB on nanocomposite. Nanocomposite showed 277.77 and 238.09 mg/g Langmuir adsorption capacity for MB and CR respectively. Desorption of dyes from the dye loaded nanocomposite was easily carried out with acetone. The results indicate that the prepared malachite@clay nanocomposite is an efficient adsorbent with high adsorption capacity for the aforementioned dyes.     

Application of activated carbon derived from scrap tires for adsorption of Rhodamine B

Activated carbon derived from solid hazardous waste scrap tires was evaluated as a potential adsorbent for cationic dye removal. The adsorption process with respect to operating parameters was investigated to evaluate the adsorption characteristics of the activated pyrolytic tire char (APTC) for Rhodamine B (RhB). Systematic research including equilibrium, kinetics and thermodynamic studies was performed. The results showed that APTC was a potential adsorbent for RhB with a higher adsorption capacity than most adsorbents. Solution pH and temperature exert significant influence while ionic strength showed little e ect on the adsorption process. The adsorption equilibrium data obey Langmuir isotherm and the kinetic data were well described by the pseudo second-order kinetic model. The adsorption process followed intra-particle di usion model with more than one process a ecting the adsorption process. Thermodynamic study confirmed that the adsorption was a physisorption process with spontaneous, endothermic and random characteristics.     

聚合氯化铝-镧改性膨润土的制备及除磷除藻研究

为快速去除富营养化水体中的磷和藻类,采用PAC(聚合氯化铝)和镧对膨润土进行复合改性,制备PLMB(聚合氯化铝-镧改性膨润土)吸附剂,并采用BET(全自动比表面及孔隙度分析仪)、SEM(扫描电镜)、FTIR(傅里叶红外光谱仪)、XRD(X射线衍射仪)、ICP-OES(电感耦合等离子发射光谱仪)和zeta电位分析仪对材料进行表征,使用吸附动力学和吸附等温线描述PLMB对磷的吸附机理,考察吸附剂用量、pH和腐殖酸对PLMB同步除磷除藻的影响. 结果表明:①PLMB表面具有很多层状结构,能够提供更多吸附位点,聚合氯化铝和镧成功负载于膨润土上,镧含量达到5.02%. ②PLMB能高效吸附水中的磷,吸附量达到57.629 mg/g,吸附等温线符合Langmuir等温吸附模型,吸附动力学符合颗粒内扩散模型和准二级动力学模型. ③当PLMB投加量为300 mg/L时,富营养化水样中浊度、SRP(可溶性活性磷)、TP(总磷)和Chla(叶绿素a)的去除率分别为98.7%、96.2%、94.1%和72.7%. ④水样pH为5~10时,pH增大对PLMB的除磷除藻性能具有促进作用. ⑤腐殖酸对SRP的去除无显著影响,对浊度、TP和Chla的去除有负面作用. 研究显示,PLMB表现出优异的磷吸附性能,能够同步去除水体中的磷和藻类,在富营养化水体的生态修复中具有较大应用价值.      

Lindet ypeF(K)沸石对Zn~(2+)的吸附研究

利用粉煤灰合成Linde type F(K)沸石吸附重金属Zn2+,考察吸附剂量、pH值、反应温度对Zn 2+吸附效果影响,研究沸石吸附Zn2+的等温线与动力学,得到了相应的模型。结果表明:吸附剂量、pH值、反应温度均对Zn2+去除效果影响显著。随着吸附剂量增大,Zn 2+去除效果不断提高,饱和吸附量逐渐减小。初始pH值为3~7时,沸石对Zn2+去除率随pH值升高迅速提高。反应温度越高,沸石吸附Zn2+到达平衡时间越短。沸石对Zn2+吸附过程符合Langmuir吸附等温式,其吸附为单分子层吸附;准二级反应动力学方程能很好描述沸石对Zn2+的吸附行为。     

Removal of phosphate by Fe-coordinated amino-functionalized 3D mesoporous silicates hybrid materials

Phosphate removal from aqueous waste streams is an important approach to control the eutrophication downstream bodies of water. A Fe(III) coordinated amino-functionalized silicate adsorbent for phosphate adsorption was synthesized by a post-grafting and metal cation incorporation process. The surface structure of the adsorbent was characterized by X-ray di raction, N2 adsoropion/desoprotion technique, and Fourier transform infrared spectroscopy. The experimental results showed that the adsorption equilibrium data were well fitted to the Langmuir equation. The maximum adsorption capacity of the modified silicate material was 51.8 mg/g. The kinetic data from the adsorption of phosphate were fitted to pseudo second-order model. The phosphate adsorption was highly pH dependent and the relatively high removal of phosphate fell within the pH range 3.0–6.0. The coexistence of other anions in solutions has an adverse e ect on phosphate adsorption; a decrease in adsorption capacity followed the order of exogenous anions: F?? > SO2?? 4 > NO??3 > Cl??. In addition, the adsorbed phosphate could be desorbed by NaOH solutions. This silicate adsorbent with a large adsorption capacity and relatively high selectivity could be utilized for the removal of phosphate from aqueous waste streams or in aquatic environment.     

Adsorptive removal of heavy metal ions from industrial effluents using activated carbon derived from waste coconut buttons

Removal of heavy metal ions from industrial effluents by the activated carbon prepared by steam activation of waste coconut buttons through batch adsorption process.     

Novel Al-doped carbon nanotubes with adsorption and coagulation promotion for organic pollutant removal

Al-doped carbon nanotubes (Al-doped CNTs) were prepared as a multifunctional integrated material of adsorbent and coagulant aid for organic pollutant removal from aqueous solution. It was observed that aluminum species were dispersed homogeneously on the surface of CNTs, and mainly anchored onto defect structures of the CNTs. The introduction of aluminium efficiently improved adsorption ability for methyl orange (MO) onto the CNTs, and maximum adsorption capacity calculated from the Langmuir isotherm model can reach 69.7 mg/g. The MO adsorption kinetics can be better described by the pseudo-second-order and pore diffusion kinetic models, and the diffusion of MO anions into pores of the Al-doped CNT adsorbent should be the rate-determining step. Thermodynamic analyses indicated that the adsorption of MO onto Al-CNTs-2.0 was endothermic and spontaneous. Moreover, adsorption capacity for MO on the Al-doped CNTs was evidently dependent on the CNT dose, solution pH and adsorbent dose. From the perspective of low-cost and multifunctional, suspension obtained during the Al-doped CNT adsorbent preparation, was tested as coagulant to remove humic acid (HA). A significant observation is that the suspension exhibited an excellent coagulation performance for HA, because abundant aluminous polymer and Al-doped CNTs existed in the suspension.     

用稻米壳吸附去除废水中的铜离子和铅离子

稻壳是一种廉价的生物质吸附剂,用于从废水中去除铜、铅离子。研究了吸附时间、pH值、加入量与粒径、金属离子初始浓度等因素对吸附去除水中铜、铅离子的影响。实验结果表明：在最佳吸附条件下,稻壳对初始浓度为4mg/L铜离子、10m班铅离子的吸附量分别为0．62和2．09mg／g,去除率分别为63％和83％。同时,Cu^2＋和Pb^2＋在天然稻壳上吸附的热力学行为与Langmuir吸附等温式吻;动力学数据研究表明,吸附满足;隹二级动力学模型。稻壳将是去除废水中Cu^＋和Pb^2＋有潜质的材料。