竹炭对水溶液中氨氮的吸附特性研究

研究了竹炭对水溶液中的氨氮的吸附特性,测定了不同竹炭粒径、溶液初始氨氮浓度、pH值、吸附时间对吸附效果的影响。结果表明:在酸性条件下,pH值增大吸附量增加较快,pH值为7时吸附效果最佳;在不同氨氮初始浓度下,竹炭吸附量随着浓度增大而急剧增加;吸附时间越长,吸附量越大,6h时达到吸附平衡,竹炭饱和吸附量最高达到0.21mg/g;竹炭颗粒粒径越小,吸附效果越显著。竹炭对氨氮的等温吸附符合Freundlich吸附等温方程式;用NaOH溶液进行再生,再生次数越多吸附量显著下降,4次再生后达到原吸附量的64%。     

碱化香蕉皮作为Pb~(2+)吸附剂的性能研究

以碱化香蕉皮吸附剂去除溶液中的Pb~(2+),考察了NaOH浓度和碱化时间对碱化效果的影响,探讨了吸附剂粒径、时间、pH、吸附剂用量、Pb~(2+)初始浓度及温度等对吸附性能的影响,并研究了吸附平衡和吸附动力学过程。结果表明,NaOH浓度为0.5 mol/L,碱化时间为8h时制备的碱化香蕉皮吸附性能较佳;最佳吸附条件为:吸附剂粒径60目,时间8h,pH为5,吸附剂用量1.0 g,Pb~(2+)初始浓度500 mg/L及温度为20℃。此时,吸附率可达74.5%,吸附量35.7 mg/g。等温吸附实验表明,碱化香蕉皮对Pb~(2+)的吸附平衡较好地符合Langmuir等温式。吸附过程动力学符合拟二级动力学模型,说明其吸附主要是单分子层的化学吸附。     

人工湿地基质吸附磷素性能及动力学研究

以铁粉和湿地常用基质(河沙)为研究对象,研究两者对污水中磷素的等温吸附特征,并运用1级和准2级动力学模型分析其吸附磷素的动力学过程,考察其吸附磷素的规律和性能.结果表明,铁粉和河沙对溶液中磷素的等温吸附特征符合非线性Langmuir方程,吸附反应在常温下能自发进行,铁粉吸附磷素反应自发程度、对磷素的吸附能力以及生成物的稳定性都大大超过河沙.结合1级和准2级动力学模型标准偏差R2值、1级动力学模型参数w与Langmuir方程理论最大吸附量Q0的相对误差以及准2级动力学模型参数Qe与Q0的相对误差,铁粉对水溶液中磷素的吸附动力学过程更符合1级动力学模型,河沙对水溶液中磷素的吸附动力学过程更符合2级动力学模型.     

磁性沸石的制备及其对水溶液中镍的吸附

以红土和人造沸石为原料,戊二醛为交联剂,成功制备出磁性沸石RAG。X射线衍射光谱(XRD)和傅立叶变换红外光谱(FTIR)表征结果表明,合成的RAG保持了红土和人造沸石的结构和特性。将该磁性吸附剂应用于对水溶液中镍的吸附,研究了pH、温度、时间、镍溶液含量、吸附剂投加量对吸附性能的影响,结果表明,RAG对水溶液中镍的吸附量随p H的升高而增大,吸附过程满足拟2级动力学模型和Freundlich等温吸附模型,3 h时达到吸附平衡,303 K时最大吸附量为23.27 mg/g,吸附剂投加量为8.0 g/L时镍的平衡质量浓度低于1.0 mg/L,满足GB 8978-1996排放标准。     

粉煤灰钾基改性沸石对磷酸根离子的吸附研究

以粉煤灰钾基改性沸石为吸附材料吸附PO43-,考察了改性沸石的投加量、溶液初始pH值、反应时间和反应温度对PO43-去除效果的影响。结果表明:改性沸石投加量对PO43-去除效果影响较大。随着投加量的增大,PO43-的去除率不断提高,而单位质量改性沸石的吸附量则减小。溶液初始pH值对PO43-的去除率影响显著,随着pH值的增大,PO43-的去除率增大。反应温度影响改性沸石吸附PO43-的速率。温度越高,吸附达到平衡的时间越短。吸附过程符合Freundlich吸附等温式和准二级吸附动力学方程。     

ZSM-5沸石对水溶液中铅离子的吸附性能

研究了ZSM-5沸石对水溶液中铅离子（Pb^2＋）的吸附性能,考察了Pb^2＋初始浓度、吸附剂用量、pH值和吸附时间等因素对吸附的影响。结果表明：ESM-5沸石对水溶液中铅离子有较好的去除效果,当其用量为40g／L时,水溶液中铅离子的吸附去除率达到96．09％;吸附过程在180min时达到吸附平衡;溶液pH值和初始浓度对水溶液中铅离子的去除也有显著的影响,中性和碱性条件下的去除率大于酸性时的去除率;平衡吸附量与吸附平衡浓度之间的关系较好符合Freundlich和Langmuir等温吸附方程所描述的规律。     

镁铝锆复合金属氧化物的制备及对硼吸附性能的研究

实验成功制备了镁铝锆复合金属氧化物。考察了硼初始浓度、溶液pH、接触时间、温度、Cl-浓度对镁铝锆复合金属氧化物对溶液中硼吸附效果的影响。结果表明,Cl-浓度对硼的吸附影响很小,在温度为25℃,镁铝锆复合金属氧化物投加量为2.5 g/L,溶液pH为6,吸附时间为300 min,硼质量浓度为200 mg/L时,对硼的吸附效果最好,吸附量可以达到34.07 mg/g。镁铝锆复合金属氧化物对硼的吸附平衡符合准二级动力学模型和Langmuir吸附等温模型。     

UA2400 B离子交换树脂对废水中铀(Ⅵ)的吸附性能研究

本文选用UA2400B离子交换树脂作为吸附材料,探究树脂对铀(VI)的吸附效果。借助FT-IR、SEM和EDS对树脂进行了表征,实验重点研究了铀溶液的pH值、初始浓度、吸附时间和温度对铀(VI)吸附的影响,探究了UA2400B树脂对铀的动力学吸附模型、等温吸附模型以及热力学参数。结果显示:溶液pH为8时吸附效果最佳;吸附5h后可达吸附平衡;吸附量随着初始铀(VI)离子浓度的增加而增加,树脂最大饱和吸附量达53.2mg/g;吸附符合准二级动力学和Langmuir等温吸附模型且该过程为吸热过程。综上,UA2400B树脂有望用于含铀废水中铀的分离去除。     

桉树遗态Fe2O3/Fe3O4/C复合材料吸附Sb（Ⅲ）的动力学和热力学研究

以制备获得的桉树遗态Fe2O3/Fe3O4/C复合材料为吸附剂,研究了Sb(Ⅲ )不同初始质量浓度和不同温度下,其对模拟废水中Sb(Ⅲ)的静态吸附特征。结果表明,初始质量浓度为5、10和50 mg/L Sb(Ⅲ)的吸附动力学曲线有相同的变化趋势,但吸附平衡时间随初始浓度的增大而提高;4种动力学模型的拟合和回归分析显示,遗态材料对Sb(Ⅲ)的吸附动力学特征很好地遵循准2级动力学模型(R2>0.99);在25、35、45℃试验条件下,遗态材料对Sb(Ⅲ)的吸附量均随着溶液平衡浓度的增加而增加,但随温度升高呈下降趋势,遗态材料对Sb(Ⅲ)的等温吸附更适合用Freundlich等温模型拟合(R2>0.97)。     

铁树叶水热炭及其去除溶液中铀U（VI）的研究

本文选用铁树叶为原料,采用温和的水热法制备出生物质炭.采用傅里叶变换红外光谱（FT-IR）探讨材料的成分,研究了溶液的初始pH值、初始铀浓度、温度和时间对吸附铀性能的影响,并从吸附热力学、动力学方面分析水热炭对U（Ⅵ）的吸附过程,探讨其吸附机理.结果表明溶液pH对吸附量的影响尤为显著,当pH为7时达到最大吸附量（54.66mg g-1）;在30 min时达到吸附平衡;吸附量随温度升高而不断增大.动力学研究结果表明铀在水热炭上的吸附符合准二级动力学模型和Langmuir吸附等温方程,Langmuir饱和吸附容量为56.5 mg g-1;热力学研究结果显示△H0=34.67 kJ mol-1,△G0＜0,吸附过程在考察温度范围内为自发的吸热反应过程.     

Study of equilibrium,kinetic and thermodynamic parameters about methylene blue adsorption onto natural zeolite

Adsorption equilibrium and kinetic of methylene blue (MB) onto natural zeolite was studied in a batch system. Variables of the system include contact time, pH, salt concentration, temperature, and initial MB concentration. The increase in temperature resulted in a higher MB loading per unit weight of the zeolite. Langmuir, Freundlich, Redlich–Peterson, Koble–Corrigan and Temkin isotherm models were applied to experimental equilibrium data of MB adsorption depending on temperature. The effect of contact time at different temperatures and initial concentration were fitted to pseudo-second-order kinetic model. Linear regressive method and nonlinear regressive method were used to obtain the relative parameters. The error analysis was conducted to find whether linear method or nonlinear method was better to predict the experimental results and which model was better to fit the experimental data. Both methods were suitable to obtain the parameters. The Redlich–Peterson equation was best to fit the equilibrium data. The pseudo-second-order kinetic model can be used to describe the adsorption behavior. The nonlinear method may be better with the absolute error as limited condition. The adsorption process was spontaneous and endothermic.     

Arsenic adsorption on goethite nanoparticles produced through hydrazine sulfate assisted synthesis method

Goethite nanoparticles synthesized using hydrazine sulfate as a modifying agent were evaluated for As(V) adsorption capacity. The nanoparticles were characterized for their morphological and structural features. The precipitated goethite particles were spherical with particle size of less than 10 nm. Batch adsorption study was carried out systematically varying parameters such as pH, contact time, initial As(V) concentration and adsorbent doses. The Langmuir isotherm represented the equilibrium data well and the estimated monolayer adsorption capacity at ambient temperature was 76 mg/g, which is significantly higher than most of the adsorbents reported in the literature. Adsorption kinetic data were better represented by the pseudo-second order kinetic model. Intra-particle diffusion played a significant role in the rate controlling process in the initial hour. Desorption study showed that the loaded adsorbent could be regenerated when treated with dilute sodium hydroxide solution of pH 13.     

EXPERIMENTAL INVESTIGATION ON ADSORPTION OF AMIDO BLACK 10B DYE ONTO ZEOLITE SYNTHESIZED FROM FLY ASH

This work presents experimental studies on adsorptive removal of Amido black 10B dye using a low-cost zeolite synthesized from fly ash to study the effect of various parameters, namely pH, temperature, agitation speed, adsorption time, zeolite loading, and dye concentration, on dye removal efficiency. Dye removal efficiency increased with increase in adsorbent dosage, adsorption time, and stirrer speed, and the optimal values of zeolite dose, adsorption time, and stirrer speed were found to be 10 g/L, 6 h, and 300 rpm respectively. On the other hand, dye removal efficiency decreased with increase in the initial dye concentration as well as temperature, indicating that the adsorption process is exothermic and is effective at low concentrations of adsorbate. Maximum dye removal was obtained at low pH values (between 2 and 5), indicating the fact that the zeolite surface is positively charged. Experimental data matched well with the pseudo-first-order kinetic model and the Freundlich equilibrium isotherm. The most important observation in this work is that zeolite synthesized from fly ash could act as a very effective adsorbent for the removal of amido black dye from its 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.     

无机离子交换剂的Na-NH4^＋离子交换特性

研究以天然沸石为基体制备无机离子交换剂的方法;利用离子交换剂的吸附等温曲线,可得到阳离子最大的交换容量;通过离子交换剂的吸附动力学曲线,可求得吸附平衡时间。结果表明,以改性剂M为改性材料,在天然沸石与改性剂M质量比为4：1时制得的无机离子交换剂的阳离子交换容量最高,常温时能达50mg／g,平衡吸附时间约为2h。     

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.     

Phosphate adsorption characteristics of alunite to be used as a cement additive

The adsorption of phosphate from aqueous solution by alunite has been investigated as a function of calcination temperature, particle size, pH, agitation time and initial phosphate concentration. Phosphate adsorption was seen to increase with increasing calcination temperature, decreasing adsorbent particle size and pH. The adsorption isotherm data were fitted to the Langmuir isotherm. The alunite exhibited the highest phosphate uptake capacity at 1073 K calcination temperature, at a particle size of 90-150 μm, at the initial pH of 5.0, at an equilibrium time of 60 min and at the initial phosphate concentration of 20×10⁻⁴ mol/l. The adsorption capacity, Q, was 4.697×10⁻³ mol/g at initial pH 5.0.     

Mechanistic,Kinetic, and Thermodynamic Evaluation of Adsorption of Hazardous Malachite Green onto Conch Shell Powder

The present study explores the ability of a new adsorbent—conch shell powder (CSP) in removing Malachite Green from aqueous solutions. The effect of various process parameters, namely initial solution pH, temperature, initial dye concentration, adsorbent dose, and contact time was investigated. Adsorption equilibrium data were well described by the Langmuir isotherm with maximum adsorption capacity of 92.25 mg g^?1 at 303 K. The kinetic data conformed to the pseudo-second-order kinetic model. A thermodynamic study showed the spontaneous nature and feasibility of the adsorption process. The results provide strong evidence to support the hypothesis of adsorption mechanism.     

镧改性核桃壳生物炭制备及吸附水体磷酸盐性能

为研发低成本的磷酸盐吸附剂,以核桃壳为原料,LaCl₃为改性试剂热解制备核桃壳生物炭。通过SEM-EDS、ICP-OES、FTIR和XRD对生物炭进行表征,采用吸附等温模型和动力学模型拟合生物炭的吸磷特征,并研究热解温度、La改性浓度、添加量、初始溶液pH和共存离子对生物炭吸附磷的影响。结果表明：La改性后,生物炭表面由于负载了La₂O₃和LaOCl,其吸附能力明显提高。热解温度为400℃、La浸渍浓度为0.1mol/L时获得的生物炭（BC-La400）,其Langmuir最大磷吸附容量为12.18mg/g,吸附过程主要受化学吸附和颗粒内扩散控制。热解温度和La改性浓度过高均不利于磷的吸附。磷初始浓度为50mg/L时,BC-La400添加量为2.7g/L可获得较理想的吸附能力,但当添加量超过4.0g/L时,磷脱除率可超过98%。BC-La400吸磷时最佳初始pH为3,CO{}_{\mathrm{3}}^{\mathrm{2}-}共存会明显削弱BC-La400对磷的吸附能力。     

硫酸钙处理含磷废水特性研究

研究工业石膏的主要成分硫酸钙对含磷废水的处理特性.讨论了废水pH、磷的初始含量、处理时间、投加量等参数对处理的影响,并对吸附等温特性进行了探讨.结果表明,硫酸钙对含磷废水具有良好的吸附作用,等温吸附特征与Langmuir方程和Temkin方程比较吻合,其吸附性能在碱性条件下较佳,初始含量对吸附影响明显,吸附规律为随着含量的增加,磷去除率逐渐减小,在磷的初始质量浓度低于20mg·L-1时,去除效果较好,可达到95%以上;随着吸附剂投加量的增加,磷去除率逐渐增大,而吸附容量逐渐减小.