多孔壳聚糖交联树脂的制备及对磷酸盐中磷的吸附

以壳聚糖为原料,二甲苯为分散剂、乙酸乙酯为致孔剂、环氧氯丙烷为交联剂,利用反相悬浮交联法制备了多孔壳聚糖交联树脂;通过红外光谱对树脂结构进行表征并对其性能参数进行了测定;系统考察了该多孔树脂对磷酸盐中磷的吸附特性,结果表明,溶液pH和温度对吸附率的影响较大,在磷酸根浓度为2 mg/L,pH=3,溶液温度为60℃时吸附率达到85.8%;吸附过程符合二级动力学吸附,符合Langmuir吸附模型,吸附为吸热、熵增、自发的过程。在7次吸附解吸循环试验中,相邻2次的吸附量变化不超过0.03 mg/g,说明多孔树脂具有良好的循环吸附稳定性。     

酸改性活性炭对EDTA废水的吸附

采用盐酸和硝酸对活性炭进行改性处理获得酸改性活性炭,并将其用于处理EDTA废水。考察改性条件(如酸的种类、改性时间和酸的浓度)、振荡速度和酸改性活性炭投加量等因素对吸附效果的影响,同时采用吸附等温模型和吸附动力学模型进行拟合分析。结果表明,采用1.0mol/L盐酸改性12h所获得的改性活性炭吸附效果最好。在EDTA初始浓度为300mg/L、溶液体积为50mL、温度为20℃、振荡速度为200r/min,改性活性炭投加量为0.2g时,48h后吸附量为47.1 mg/g,吸附率为62.8%;而当改性活性炭投加量增加到2.0g时,吸附率达到93.8%。改性活性炭对EDTA的吸附很好地符合Langmuir吸附等温模型(0.9963),其吸附动力学行为可用Bangham动力学方程和准二级动力学方程来描述。     

活性炭负载Fe(Ⅲ)氧化物去除水中的磷酸根

利用活性炭负载铁氧化物制备了复合吸附剂,并用于水中磷酸根的去除.采用BET,SEM及XRD等手段对复合吸附剂的物理化学特性进行了表征,用静态吸附实验方法比较研究了复合吸附剂和活性炭从水溶液中吸附磷酸根的性质.结果表明:复合吸附剂具有快的吸附速度和高的吸附容量,其吸附磷酸根的性质受溶液pH值、铁含量及阴离子浓度的影响.在pH=3.0时,复合吸附剂对磷酸根的吸附容量为98.39 mg/g,而活性炭为78.90 mg/g.相比之下,Freundlich模型比Langmuir模型能更好地描述复合吸附剂和活性炭对磷酸根的吸附过程;而Lagergren二级方程却能很好地描述复合吸附剂对磷酸根的吸附动力学.水合氧化铁/活性炭复合吸附剂吸附磷酸根为吸热过程.     

提取腐植酸后的天祝褐煤残渣对污水中Cr(Ⅵ)的吸附性能

天祝褐煤资源丰富,其提取腐植酸后的残渣对污水中的有害物质有一定的吸附能力.为此,制备了天祝褐煤提取腐植酸后的残渣,研究了其对污水中重金属离子Cr(Ⅵ)的吸附性能.结果表明:在室温(20～25℃),pH值为5的条件下,褐煤残渣对Cr(Ⅵ)有较好的吸附性能,吸附平衡时间约为4 h;吸附规律符合Freundlich吸附等温式,其相关系数R2为0.968 6,特性常数n为2.044 6,其吸附过程可用Ho准二级反应动力学模型描述.     

提取腐植酸后的天祝褐煤残渣对污水中Cr(VI)的吸附性能

天祝褐煤资源丰富,其提取腐植酸后的残渣对污水中的有害物质有一定的吸附能力。为此,制备了天祝褐煤提取腐植酸后的残渣,研究了其对污水中重金属离子Cr(Ⅵ)的吸附性能。结果表明:在室温(20～25℃),pH值为5的条件下,褐煤残渣对Cr(VI)有较好的吸附性能,吸附平衡时间约为4h;吸附规律符合Freundlich吸附等温式,其相关系数R2为0.9686,特性常数n为2.0446,其吸附过程可用Ho准二级反应动力学模型描述。     

5种改性淀粉吸附Cu~(2+)性能及动力学研究

具有一定功能基团的改性淀粉可提高对重金属离子的吸附能力,分别以阳离子淀粉、磷酸酯淀粉、磷酸酯双淀粉、氧化淀粉和尿素淀粉5种改性淀粉为吸附剂,以紫外分光光度法测量吸附后的Cu~(2+)质量浓度,考察了改性淀粉对Cu~(2+)的吸附动力学,并对比了不同改性淀粉的吸附效果。结果表明,在改性淀粉用量为0.1g、铜离子初始浓度为2g/L、溶液体积为100mL的条件下饱和吸附,其中磷酸酯淀粉吸附量最大,达50.7mg/g。吸附动力学研究表明5种改性淀粉的吸附等温数据均符合Freundlich模型。阳离子淀粉吸附数据符合准二级动力学模型,其余4种改性淀粉吸附数据更符合准一级动力学模型。     

罗非鱼鱼鳞对水中结晶紫的吸附特性和机理研究

通过吸附实验,考察鱼鳞投入量、结晶紫初始浓度和溶液pH等因素对罗非鱼鳞吸附水中结晶紫性能的影响,并通过红外光谱、BET比表面积、扫描电镜、吸附动力学和吸附等温线来分析吸附机理。结果表明:当溶液pH为7、温度30℃,吸附剂投加量为3g/L、吸附时间为20min,结晶紫浓度为40mg/L时,吸附效果最好,结晶紫的吸附率和吸附容量可分别达到66.69%和8.27mg/g;鱼鳞对结晶紫的吸附过程符合Lagergren准二级动力学模型,吸附过程属于物理吸附;吸附等温线符合Freundlich吸附等温式,当温度30℃时鱼鳞对结晶紫的最大吸附量为18.9mg/g;且罗非鱼鱼鳞中的胶原蛋白和羟基鳞灰石均参与了结晶紫染料的吸附。     

柠檬酸接枝苎麻纤维铀吸附及抗菌性能EI北大核心CSCD

核能开发会产生大量含铀废水,危害生态环境和人类健康。文中通过酯化法制备了柠檬酸接枝苎麻纤维吸附剂,用于去除水溶液中的铀。研究了铀酰离子初始浓度、溶液pH值、吸附时间、温度等条件对吸附剂性能的影响。结果表明,当铀酰离子初始浓度为20mg/L、溶液pH=6、吸附剂的投加量为0.02g/L、吸附时间为12h时达到吸附平衡,最大吸附容量为397mg-U/g;吸附过程符合Langmuir模型和准二级动力学模型。另外,吸附剂对大肠杆菌具有明显的抑制作用,表现出良好的抗菌性能。     

黑藻对含重金属废水中锌离子的吸附性能

黑藻能吸附重金属废水中的Zn2+,但对其的报道鲜见.研究了生物吸附剂黑藻对废水中Zn2+的吸附去除性能,考察了溶液pH值、Zn2+初始浓度、黑藻加入量和吸附时间对吸附效果的影响.同时通过EDX分析和等温吸附模型对黑藻吸附Zn2+的机理进行了研究.结果表明:在溶液pH值为6.0、黑藻加入量为2 g/L,吸附时间为30 min,Zn2+质量浓度为20 mg/L的条件下,黑藻对Zn2+的吸附率为85%,并且发现黑藻对Zn2+的吸附是阳离子交换过程,吸附符合Langmuir,Freuncllich和D-R等温吸附模型.     

改性膨润土对溶液中Co2+、Mn2+的吸附研究

以膨润土为原材料,盐酸为改性剂,制备改性膨润土。研究了改性膨润土的制备条件,其对重金属Co2+、Mn2+的吸附性能及对苯二甲酸(PTA)工业中的副产品对甲苯甲酸对吸附的影响。实验结果表明,盐酸的最佳改性浓度为1.5mol/L,改性膨润土在40℃的吸附能力最好,可达到12～14mg/g,经过热力学分析得出,改性膨润土对钴离子、锰离子的吸附方式均符合Langmuir吸附模型,PTA工业中的副产品对甲苯甲酸对吸附没有影响。     

DF-3絮凝剂产生菌培养条件的优化

从花园土壤中筛选到一株有絮凝能力的菌株编号为DF-3,在温度为30℃,通气量（以摇床转速表示）为160r／min时通过实验确定DF-3的最佳培养条件：初始pH为8;20g／L果糖和5g／L葡萄糖为碳源;0．3g／L蛋白胨,0．5g／L酵母膏,0．5g／L尿素和0．2g／L（NH4）2SO4为最佳氮源;无机盐为2g／LKH2PO4,5g／L K2HPO4和0．1g／L NaCl。在这种条件下培养36小时所产微生物絮凝剂对高岭土悬浊液的絮凝率超过90％。     

吐温-60对钢在H2SO4中的缓蚀性能

用失重法研究了非离子表面活性剂吐温-60对冷轧钢在0.5-7.0 mol/L H2SO4溶液中的缓蚀作用。结果表明：吐温-60对冷轧钢在1.0 mol/L H2SO4溶液中具有良好的缓蚀作用,且在钢表面的吸附符合校正的Langmuir吸附模型。缓蚀率随缓蚀剂浓度的增加而增大,但随温度和硫酸浓度的增加而减小。求出了相应的吸附热力学（吸附自由能ΔG^0, 吸附焓ΔH^0, 吸附熵ΔS^0）和动力学参数（腐蚀速率常数k, 腐蚀动力学常数B）,并根据这些参数讨论了缓蚀作用机理。     

Characteristics and mechanisms of phosphate adsorption onto basic oxygen furnace slag

The adsorption characteristics of phosphate adsorption on the basic oxygen furnace (BOF) slag were identified as a function of pH and ion strengths in solution. In addition, adsorption mechanisms were investigated by conducting batch tests on both the hydrolysis and phosphate adsorption process of the BOF slag, and making a comparative analysis to gain newer insights into understanding the adsorption process. Results show that the adsorption capacity from 4.97 to 3.71 mgP/g slag when the solution pH was increased from 2.0 to 13.0 and phosphate initial concentration was 50 mg/L, indicating that adsorption capacity is largely dependent upon the pH of the system. The results of the competitive adsorption between phosphate and typical anions found in wastewater, such as NO(3)(-), SO(4)(2-) and Cl(-), onto BOF slag reveal that BOF slag can selectively adsorb phosphate ions. The insignificant effect of NO(3)(-), SO(4)(2-) and Cl(-) on phosphate adsorption capacity indicates that phosphate adsorption is through a kind of inner-sphere complex reaction. During the adsorption process, the decrease of phosphate concentration in solution accompanied with an increase in pH values and concentrations of NO(3)(-), SO(4)(2-) and Cl(-) suggests that phosphate replaced the functional groups from the surface of BOF slag which infers that ligand exchange is the dominating mechanism for phosphate removal. At the same time, the simultaneous decreases in PO(4)(3-) and total calcium, magnesium and aluminum concentration in solution indicate that chemical reaction and precipitation are other mechanisms of phosphate removal.     

Advanced treatment of liquid swine manure using physico-chemical treatment

In this study, liquid swine manure was treated by physico-chemical treatment, including coagulation, flocculation, and sedimentation followed by an oxidation step as a polishing treatment at a bench-scale level. A superabsorbent polymer (SAP) and a mineral and salt formulation able to generate molecular iodine were used as coagulant and oxidant agents, respectively. The results indicated that SAP at a concentration of 1.25 g/L was able to reduce 32% of the initial total suspended solids (TSS) in experiments using supernatant at its natural pH. Following the SAP application, 82% of initial ammonia (NH(3)), 78% of initial total organic carbon (TOC), and 93% of the total coliforms were reduced using 40 mg/L of free iodine. In experiments performed with diluted supernatant (five-fold dilution), it was found that SAP at a concentration of 0.5 g/L was capable of reducing 80% of the initial TSS in experiments at pH 11. A leaching study was conducted to assess the safety of sludge disposal. From the leaching tests using non-diluted supernatant, it was found that 24% of the chloride (Cl(-)) and 50% of the phosphate (PO(4)(3-)) ions retained in the sludge leached to the ultrapure water after 48 h. Potential contamination due to leaching of NH(3), nitrite (NO(2)(-)) and nitrate (NO(3)(-)) was found to be statistically insignificant.     

Removal of phosphate by mesoporous ZrO2

A type of mesoporous ZrO2 was synthesized and its phosphate removal potential was investigated in this study. The adsorption isotherm, pH effect, ionic strength effect and desorption were examined in batch experiments. The adsorption data fitted well to the Langmuir model with which the maximum P adsorption capacity was estimated to be 29.71 mgP/g. The amount of phosphate adsorbed increased rapidly in the first 5 h and slowly towards the end of the run, suggesting the possible monolayer coverage of phosphate ions on the surface of the adsorbent. The phosphate adsorption tended to increase with a decrease of pH and an increase of ionic strength. A phosphate desorbability of approximately 60% was observed with 0.5 M NaOH, which indicated a relatively strong bonding between the adsorbed PO4(3-) and the sorptive sites on the surface of the adsorbent. The immobilization of phosphate probably occurs by the mechanisms of ion exchange and physicochemical attraction. Due to its high adsorption capacity, this type of Zirconium oxide has the potential for application to control phosphorus pollution.     

Defluoridation from aqueous solutions by nano-alumina: characterization and sorption studies

The present study was conducted to evaluate the feasibility of nano-alumina (Al(2)O(3)) for fluoride adsorption from aqueous solutions. The nature and morphology of pure and fluoride-sorbed nano-alumina were characterized by SEM with EDX, XRD, and FTIR analysis. Batch adsorption studies were performed as a function of contact time, initial fluoride concentration, temperature, pH and influence of competing anions. Fluoride sorption kinetics was well fitted by pseudo-second-order model. The maximum sorption capacity of nano-alumina for fluoride removal was found to be 14.0 mg g(-1) at 25°C. Maximum fluoride removal occurred at pH 6.15. The fluoride sorption has been well explained using Langmuir isotherm model. Fluoride sorption was mainly influenced by the presence of PO(4)(3-), SO(4)(2-) and CO(3)(2-) ions.     

Phosphate removal using sludge from fuller's earth production

This study assesses the phosphate removal capacity and mechanism of precipitation or adsorption from aqueous solutions in batch experiments by an industrial sludge containing gypsum (CaSO(4).2H(2)O) obtained as a by-product from a fuller's earth process. The potential capacity for phosphate removal was tested using various solution concentrations, pH values, reaction times, and amount of sludge. The maximum phosphate adsorption capacity calculated using the Langmuir equation was 2.0 g kg(-1). The pH for the maximum adsorption by the sludge was neutral to alkaline (pH 7-12). Over 99% of phosphate was removed from a phosphate solution of 30 mg L(-1) using 0.15 g of sludge in a 9-h reaction. Sulfate (SO(4)(2-)) concentration increased with increasing initial phosphate concentration, possibly because of dissolution of gypsum and adsorption of both sulfate and phosphate. At high phosphate concentration (>1000 mg L(-1)), relative constant concentration of Ca(2+) was not consistent with adsorption of the most important phosphate removal mechanism. Results suggest that precipitation of calcium phosphate is principally responsible for phosphate removal under its high concentration. Agglomerated precipitate in the reaction sludge was observed by SEM and identified as brushite (CaHPO(4).2H(2)O) by XRD, FT-IR, and DTA. Based on thermodynamic considerations, it is suggested that the brushite will readily transform to more stable phases, such as hydroxyapatite (Ca(5)(PO(4))(3).OH).     

Adsorption of ammonium dinitramide (ADN) from aqueous solutions. 1. Adsorption on powdered activated charcoal

Investigations on the adsorption of ammonium dinitramide (NH(4)N(NO(2))(2)) (ADN) from aqueous solutions on powdered activated charcoal (PAC) were carried out in order to find out an effective and easier method of separating ADN from aqueous solutions. The effectiveness of PAC in the selective adsorption of ADN from aqueous solutions of ADN (ADN-F) and ADN in presence of sulfate (SO(4)(2-)) and nitrate (NO(3)(-)) ions (ADN-PS) was examined and compared using batch and column methods. The adsorption process follows both Langmuir and Freundlich adsorption isotherms and the isotherm parameters for the models were determined. The observed data favor the formation of monolayer adsorption. The adsorption capacities were found to be 63.3, 119, 105.3 and 82 mg of ADN per g of PAC for ADN-F (batch), ADN-PS (batch), ADN-F (column) and ADN-PS (column), respectively. Break-through curves for ADN-F and ADN-PS were obtained for the optimization of separation of ADN from aqueous solutions. Elution curves were generated for the desorption of ADN from PAC using hot water as eluent.     

Ammonium exchange in leakage waters of waste dumps using natural zeolite from the Krapina region, Croatia

The paper presents the results of investigating the treatment of leakage waters from waste dumps using activated carbon and natural zeolite clinoptilolite, known as a very selective and efficient cation exchanger for ammonium ions. The results are presented of chemical and physical analyses of leakage waters characterized by a high content of ammonium (820 mg L(-1)) and organic pollutants (1033 mg L(-1) C). Physical and chemical characteristics of zeolite and the exchange of ammonium ions in model and real solutions were determined in laboratory trials. Treatment of leakage water with 0.04-2.5% (w/w) activated carbon (Norit 0.8 Supra) led to a reduction of total organic carbon in leakage water from 1033 to 510 mg L(-1). Pretreatment of leakage water with activated carbon did not improve the exchange of ammonium ions on zeolite. Without pretreatment of leakage water, the exchange of ammonium ions amounted to 4.2 mg NH4+/g zeolite. Addition of activated carbon, regardless of its mass, increased the exchange of ammonium ions to only 5.7 mg NH4+/g zeolite. In the model solution of an equal concentration of ammonium as the real solution, 17.70 mg NH4+/g zeolite was exchanged. Organic pollutants that were not eliminated by activated carbon (most probably components of natural origin) adsorbed to zeolite and prevented the exchange of NH4+ ions, which was also reduced due to the presence of K+ and Ca2+ ions.     

Kinetics and mechanism of arsenate removal by nanosized iron oxide-coated perlite

This study discussed the adsorption kinetics of As(V) onto nanosized iron oxide-coated perlite. The effects of pH, initial concentration of As(V) and common anions on the adsorption efficiency were also investigated. It was observed that a 100% As(V) adsorption was achieved at pH value of 4-8 from the initial concentration containing 1.0 mg-As(V)L(-1) and the adsorption percentage depended on the initial concentration; the phosphate and silicate ions would not interfere with the adsorption efficiency. Furthermore, nanosized iron oxide-coated perlite (IOCP) has been shown to be an effective adsorbent for the removal of arsenate from water. The adsorption kinetics were studied using pseudo-first- and pseudo-second-order models, and the experimental data fitted well with the pseudo-second-order model. Moreover, it suggests that the Langmuir isotherm is more adequate than the Freundlich isotherm in simulating the adsorption isotherm of As(V). The adsorption rate constant is 44.84 L mg(-1) and the maximum adsorption capacity is 0.39 mg g(-1). These findings indicate that the adsorption property of IOCP gives the compound a great potential for applications in environmental remediation.