核桃壳对模拟废水中Cu~(2+)的吸附性能研究

采用核桃壳作为吸附剂,对模拟废水中的Cu2+进行吸附去除,考察了吸附剂粒径、水样初始pH、吸附剂用量、Cu2+初始浓度、吸附时间等因素对Cu2+吸附效果的影响,确定最佳吸附参数,并进行了吸附动力学和吸附等温线分析。结果表明:最佳吸附参数为核桃壳吸附剂粒径1.25~1.60mm、水样初始pH 5.0、吸附剂用量2.5g,Cu2+初始质量浓度20mg/L、吸附时间360min,在此条件下100mL水样在200r/min、25℃条件下吸附的Cu2+去除率达70%以上,吸附量约为0.702mg/g;本实验过程采用伪二级动力学方程的拟合更好,R2均在0.9以上,Cu2+吸附速率与其浓度的二次方成正比;Langmuir方程可以较好地描述核桃壳吸附剂对Cu2+的吸附过程,此吸附过程是单分子层的吸附。     

核桃壳粉对水溶液中Pb2＋的吸附

实验通过间歇吸附方式研究了核桃壳粉对水溶液中Pb^2＋的吸附特性，探讨了核桃壳粉粒径及用量、溶液pH、Pb^2＋初始浓度等参数对吸附的影响，并讨论了吸附过程的热力学和动力学特征。结果表明，核桃壳粉对Pb^2＋吸附的最佳pH为5．0，去除率随吸附剂粒径的减小、用量的增加、Pb^2＋初始浓度的减小而增加。优化实验条件下，0～0．3mm15g／L的吸附剂在298K时，对pH=5的50mL50mg／LPb^2＋溶液的去除率达96．98％。核桃壳粉对Pb^2＋的吸附等温线符合Sips模型，在283、293和303K的最大吸附量分别为18．25、18．27和20．94mg／g。吸附过程是放热的、混乱度减小的自发过程，且符合准二级动力学模型。吸附速率常数随温度升高而减小，在293和303K时分别在90和120min基本达到平衡。结合FTIR和SEM手段发现核桃壳对Pb^2＋的吸附以物理吸附为主，同时包括离子交换、螯合等化学吸附以及颗粒内扩散步骤，是一个复杂的过程。     

柠檬酸改性核桃壳粉负载纳米零价铁的制备及EDTA优化去除四环素

为解决纳米零价铁(NZVI)因团聚而导致的反应活性降低问题,通过液相还原法合成新型柠檬酸改性核桃壳粉负载纳米零价铁(CA-WNS-NZVI)的复合材料,添加EDTA条件下对四环素(TC)进行去除研究。柠檬酸改性可以增加核桃壳粉表面的羧基基团,有助于提高NZVI的负载量和分散性;在反应体系中存在EDTA的情况下,CA-WNS-NZVI对TC去除率达到99.02%,而在无EDTA条件下,TC去除率仅为82.10%。系统地研究了TC初始浓度、pH、温度和EDTA浓度对TC去除效果的影响。CA-WNS-NZVI的SEM表征揭示了NZVI均匀地分布在CA-WNS-NZVI上。CA-WNS-NZVI复合材料的XRD和FT-IR谱图表明NZVI成功地负载在核桃壳表面。同时讨论了EDTA优化CA-WNS-NZVI复合材料对TC去除的反应机制。新型CA-WNS-NZVI复合材料有望为抗生素废水治理提供新思路和新技术方法。     

氮炭化核桃壳对Cr(Ⅵ)的吸附特性与机理

采用新疆核桃壳为原材料,将其在氮气氛围下炭化,制备氮炭化核桃壳吸附剂,利用静态吸附法研究了其对模拟废水中低浓度Cr(Ⅵ)的吸附性能,并采用SEM和FTIR技术对该吸附剂进行表征。结果表明,Langmuir等温吸附方程可以更好地拟合氮炭化核桃壳对Cr(Ⅵ)的吸附过程,说明Cr(Ⅵ)在氮炭化核桃壳上的吸附属于单分子层吸附,25℃时,当pH为2.0、吸附剂用量为16 g·L~(-1)、吸附时间为180 min、转速为200 r·min~(-1)时,Cr(Ⅵ)的去除率达到99.1%,饱和吸附容量为8.751 mg·g~(-1)。吸附动力学分析结果表明,该动态吸附平衡遵循拟二级动力学方程。表征结果显示,氮炭化核桃壳表面较粗糙,孔隙轮廓更清晰,更有利于对Cr(Ⅵ)的吸附,吸附过程中Cr(Ⅵ)主要与氮炭化核桃壳表面的O—H、CO、N—H、C—O—C等活性基团发生了作用。     

虾壳粉对水溶液中阴、阳离子型染料的吸附

采用废弃虾壳制备吸附剂处理含刚果红或亚甲基蓝的溶液。考察了温度、吸附时间、初始浓度、吸附剂投加量和初始溶液pH对吸附效果的影响并构建了去除率预测模型,并对吸附等温线、吸附动力学和吸附热力学进行系统研究。结果表明:虾壳粉对刚果红和亚甲基蓝的吸附分别在24 h和4 h时达到平衡,平衡吸附量随吸附时间、初始浓度及吸附剂投加量的增加而增大;刚果红平衡吸附量随pH升高而增大,亚甲基蓝平衡吸附量几乎不随pH变化。在15℃下,吸附剂投加量为1 g·L~(-1),刚果红吸附的最优条件为接触时间24 h、pH=4,在该条件下,虾壳粉对刚果红的饱和吸附量为276.64 mg·g~(-1);亚甲基蓝吸附的最优条件为接触时间4 h、pH=12,在该条件下,虾壳粉对刚果红的饱和吸附量为1.44 mg·g~(-1);虾壳粉对2种染料的吸附过程以物理吸附为主,符合准二级动力学方程。虾壳粉对阴离子型染料的吸附效果较优,对阳离子型染料有一定吸附性能,是一种经济高效的染料废水吸附材料。     

基于响应曲面法优化生物质污泥活性炭的制备方法

针对传统技术制备污泥活性炭的比表面积不高、吸附值低等不足,通过在污泥中添加核桃壳以改善污泥原料缺陷,研究了活化剂种类、核桃壳加量、活化温度、活化时间、活化剂浓度及浸渍比等影响活性炭吸附能力的制备条件。在优化后的条件下制备出了高吸附性能的生物质污泥复合活性炭。结果表明:选择氯化锌作为活化剂,核桃壳加量20%、活化温度500℃、活化时间60 min、活化剂浓度2.5 mol·L-1、浸渍比1∶2.5为最优化制备条件。制备出的生物质污泥复合活性炭碘吸附值为574.11 mg·g-1,产率为43.93%。     

无机柱撑膨润土对有机锡废水中锡的吸附研究

利用天然膨润土、羟基铁和羟基铁铝柱撑膨润土进行了吸附有机锡废水中总锡的实验.研究了膨润土投加量、pH、吸附时间和吸附等温线的变化规律.结果表明,达到吸附平衡的时间为1 h;总锡的吸附去除率最佳吸附pH在6.0～9.0;膨润土的投加量大于10 g/L时,总锡吸附去除率可达到最大值;总锡在天然膨润土上的吸附符合Freundlich吸附等温方程,而总锡在柱撑膨润土上的吸附同时符合Freundlich和Langmuir吸附等温方程;柱撑膨润土吸附活性位的数量是决定吸附性能的关键因素.在对总锡的吸附过程中,膨润土吸附容量的大小和吸附作用强弱的顺序为:羟基铁铝柱撑膨润土＞羟基铁柱撑膨润土＞天然膨润土.     

核桃壳炭化吸附废水中Cr(Ⅵ)的性能研究

采用氯化锌活化法制备生物质废物硬壳活性炭,工艺条件为:核桃壳与氯化锌溶液质量比为1∶1.5、氯化锌溶液质量分数50%、炭化温度300℃、炭化时间90 min、活化温度600℃、活化时间60 min。对产品比表面积、孔径和表征进行了分析,并探讨了该核桃壳活性炭吸附废水中六价铬的pH值、废水初始浓度、吸附时间、振动转速等影响因素。结果表明:制得的活性炭碘吸附值为1 038.33 mg/g,比表面积为645.36 m2/g,平均孔半径为1.37 nm。当活性炭用量为0.1 g,废水pH=3,吸附接触时间为1 h,取100 mL浓度为50 mg/L的含Cr6+废水时,处理吸附量可达48.57 mg/g。活性炭最大饱和吸附值为80.24 mg/g。吸附符合Langmuir等温模式,吸附等温方程式为Ce/Qe=0.0083+0.0121Ce。     

纳米羟基铁改性活性炭对亚甲基蓝的吸附性能研究

采用乙醇分散法制备了纳米羟基铁修饰的玉米苞叶和竹笋壳的活性炭复合物(记为nFeOOH@AC),分析了nFeOOH@AC对水样中亚甲基蓝的吸附性能及动力学机理。研究表明,nFeOOH@AC对亚甲基蓝的吸附以化学吸附为主,符合准二级动力学模型。在亚甲基蓝初始质量浓度为3～120 mg/L,体积为50 mL,nFeOOH@AC投加量为10 mg, pH为3～12,吸附时间为1～24 h时,吸附率随着pH升高而增大,随着亚甲基蓝初始浓度的增大先增后减,随着吸附时间的增加而增加。nFeOOH@AC可以作为一种新型环境友好型吸附剂应用于亚甲基蓝废水处理。     

粉质粘土和粉质砂土对铬渣渗滤液中Cr(Ⅵ)吸附特性

针对铬渣堆场及其渗滤液生态环境污染严重这一热点问题，在对锦州铬渣堆场附近不同土壤取样测定基础上，采用振荡平衡法，测定吸附时间、污染物浓度、pH值、温度等条件改变对粉质粘土和粉质砂土吸附Cr（Ⅵ）的影响，研究2种土壤对Cr（Ⅵ）的吸附特性，获得土壤吸附的等温吸附曲线，建立吸附动力学方程。结果显示，吸附时间、污染物浓度、pH值、温度等都对土壤吸附Cr（Ⅵ）有不同程度的影响。粉质粘土和粉质砂土对Cr（Ⅵ）的吸附可用Langmuir方程、Freundlich方程和Temkin方程很好地描述，以Freundlich方程为最佳。粉质粘土和粉质砂土的Elovich型公式、双常数速率公式、抛物线扩散公式3种动力学方程的拟合程度顺序均为：Elovich型公式>双常数速率公式>抛物线扩散公式，粉质粘土相较粉质砂土动力学拟合程度更高且吸附性更好。     

Studies on removal of metal ions and sulphate reduction using rice husk and Desulfotomaculum nigrificans with reference to remediation of acid mine drainage

The utility of rice husk as an adsorbent for metal ions such as iron, zinc and copper from acid mine water was assessed. The adsorption isotherms exhibited Langmuirian behavior and were endothermic in nature. The free energy values for adsorption of the chosen metal ions onto rice husk were found to be highly negative attesting to favorable interaction. Over 99% Fe(3+), 98% of Fe(2+) and Zn(2+) and 95% Cu(2+) uptake was achieved from acid mine water, with a concomitant increase in the pH value by two units using rice husk. The remediation studies carried out on acid mine water and simulated acid mine water pretreated with rice husk indicated successful growth of Desulfotomaculum nigrificans (D. nigrificans). The amount of sulphate bioreduction in acid mine water at an initial pH of 5.3 was enhanced by D. nigrificans from 21% to 40% in the presence of rice husk filtrate supplemented with carbon and nitrogen. In simulated acid mine water with fortified husk filtrate, the sulphate reduction was even more extensive, with an enhancement to 73%. Concurrently, almost 90% Fe(2+), 89% Zn(2+) and 75% Cu(2+) bioremoval was attained from simulated acid mine water. Metal adsorption by rice husk was confirmed in desorption experiments in which almost complete removal of metal ions from the rice husk was achieved after two elutions using 1M HCl. The possible mechanisms of metal ion adsorption onto rice husk and sulphate reduction using D. nigrificans are discussed.     

Fe_3O_4/SDS磁性纳米颗粒吸附水体中的Cd~（2＋）和Zn~（2＋）

一种新型纳米固相萃取吸附剂,由阴离子表面活性剂十二烷基磺酸钠（SDS）包裹在Fe3O4磁性纳米颗粒表面形成,用于吸附水溶液中的重金属离子。研究了吸附过程的主要影响因素（如SDS浓度、溶液pH等）以及解吸过程的最佳条件,并对其机理进行了初步的探讨。研究结果表明,共沉淀法制备的Fe3O4颗粒粒径分布均匀,平均粒径约为54 nm;SDS浓度为300 mg/L时,Fe3O4/SDS磁性纳米颗粒吸附Cd2＋和Zn2＋的能力最强;在一定浓度范围内,Fe3O4/SDS体系对Cd2＋和Zn2＋的吸附平衡数据符合Langmuir吸附等温方程,饱和吸附量分别为22.42 mg/g和13.95 mg/g。最终结果表明,Fe3O4/SDS磁性纳米颗粒具有较强磁分离能力和较好的吸附效果。     

Fe3O4/SDS磁性纳米颗粒吸附水体中的Cd2+和Zn2+

一种新型纳米固相萃取吸附剂,由阴离子表面活性剂十二烷基磺酸钠(SDS)包裹在Fe3O4磁性纳米颗粒表面形成,用于吸附水溶液中的重金属离子。研究了吸附过程的主要影响因素(如SDS浓度、溶液pH等)以及解吸过程的最佳条件,并对其机理进行了初步的探讨。研究结果表明,共沉淀法制备的Fe3O4颗粒粒径分布均匀,平均粒径约为54 nm;SDS浓度为300 mg/L时,Fe3O4/SDS磁性纳米颗粒吸附Cd2+和Zn2+的能力最强;在一定浓度范围内,Fe3O4/SDS体系对Cd2+和Zn2+的吸附平衡数据符合Langmuir吸附等温方程,饱和吸附量分别为22.42 mg/g和13.95 mg/g。最终结果表明,Fe3O4/SDS磁性纳米颗粒具有较强磁分离能力和较好的吸附效果。     

Removal of azo dye from water by magnetite adsorption-Fenton oxidation.

The aim of this study is to highlight the possibility of using powder magnetite adsorption-Fenton oxidation as a method for removal of azo dye acid red B (ARB) from water. The adsorption properties of magnetite powder towards ARB were studied. The oxidation of adsorbed ARB and regeneration of magnetite adsorbent at the same time by Fenton reagent (hydrogen peroxide [H2O2] + iron (II) [Fe2+]) in another treatment unit with a smaller volume was also investigated. The efficiency of Fenton oxidation of ARB was compared for the reaction carried out in solution and on magnetite. The magnetic separation method was used to recover magnetite after adsorption or regeneration. The results indicated that the adsorption rate was fast. The capacity was strongly dependent on pH and inorganic anions, and pH 3.8 was optimal for the adsorption of ARB. The adsorption can be described well using the Langmuir model. The oxidation was more efficient for ARB adsorbed on magnetite than in solution. The adsorption capacity of magnetite increased significantly after regeneration, which was the result of an increase in surface area of the adsorbent and change of elemental ratio (oxygen:iron [O:Fe]) on the surface. The maximum adsorption capacity for ARB was 32.4 mg/g adsorbent.     

掺Al-TiO2改性膨润土去除微污染水中COD和NH4-N

采用掺Al-TiO2作为改性剂制备改性膨润土,考察了微波辐射功率、辐射时间、TiO2改性剂用量、铝盐掺杂量、pH值对微污染水中COD和NH4-N去除效果的影响。实验表明,微波辐射功率为460 W,辐射时间为8 min,TiO2改性剂用量为1.3 mmol/g,铝盐掺杂量为0.2 mmol/g为最佳制备条件。pH值为6.0,改性膨润土投加量为40 mg/L,沉淀时间为30min时,对微污染水中初始浓度15 mg/L的COD和5 mg/L的NH4-N去除率分别达到92%和59%以上。     

超声波技术处理微污染水的实验研究

通过实验,对使用超声波技术处理微污染水的效果、机理进行了初步研究,实验结果表明,超声波对微污染水的细菌和色度去除效果明显,细菌的去除符合一级反应动力学方程,对COD和浊度去除有一定效果,但不显著。结果还发现,水体pH值随时间呈上升趋势。     

Zr-Fe双组分复合除砷吸附剂的优化制备及性能评价

实验发现,铁氧化物或铁的羟基氧化物对As(V)有较好的吸附性能,而锆氧化物或锆水合氧化物则对As(Ⅲ)有优异的吸附选择性,但其使用的pH通常要在9的条件下。通过简单的共沉淀法制备了Zr-Fe双组分复合吸附剂,在制备过程中通过优化制备条件如:沉淀剂浓度、金属离子总浓度、金属离子配比、反应温度、反应时间及吸附剂价格等因素,最终合成出了对As(V)和As(Ⅲ)都具有良好吸附能力的吸附剂。这种吸附剂在中性条件下对As(V)和As(Ⅲ)的最大吸附量为62 mg/g和118 mg/g。     

Removal of arsenic from groundwater by granular titanium dioxide adsorbent

A novel granular titanium dioxide (TiO2) was evaluated for the removal of arsenic from groundwater. Laboratory experiments were carried out to investigate the adsorption capacity of the adsorbent and the effect of anions on arsenic removal. Batch experimental results showed that more arsenate [As(V)] was adsorbed on TiO2 than arsenite [As(III)] in US groundwater at pH 7.0. The adsorption capacities for As(V) and As(III) were 41.4 and 32.4 mgg(-1) TiO2, respectively. However, the adsorbent had a similar adsorption capacity for As(V) and As(III) (approximately 40 mgg(-1)) when simulated Bangladesh groundwater was used. Silica (20 mgl(-1)) and phosphate (5.8 mgl(-1)) had no obvious effect on the removal of As(V) and As(III) by TiO2 at neutral pH. Point-of-entry (POE) filters containing 3 l of the granular adsorbent were tested for the removal of arsenic from groundwater in central New Jersey, USA. Groundwater was continuously passed through the filters at an empty bed contact time (EBCT) of 3 min. Approximately 45,000 bed volumes of groundwater containing an average of 39 microgl(-1) of As(V) was treated by the POE filter before the effluent arsenic concentration increased to 10 microgl(-1). The total treated water volumes per weight of adsorbent were about 60,000 l per 1 kg of adsorbent. The field filtration results demonstrated that the granular TiO2 adsorbent was very effective for the removal of arsenic in groundwater.     

Zr—Fe双组分复合除砷吸附剂的优化制备及性能评价

实验发现，铁氧化物或铁的羟基氧化物对As（V）有较好的吸附性能，而锆氧化物或锆水合氧化物则对As（Ⅲ）有优异的吸附选择性，但其使用的pH通常要在〉9的条件下。通过简单的共沉淀法制备了Zr-Fe双组分复合吸附剂，在制备过程中通过优化制备条件如：沉淀剂浓度、金属离子总浓度、金属离子配比、反应温度、反应时间及吸附剂价格等因素，最终合成出了对As（V）和As（Ⅲ）都具有良好吸附能力的吸附剂。这种吸附剂在中性条件下对As（V）和As（Ⅲ）的最大吸附量为62mg／g和118mg／g。     

Oxidized multiwalled carbon nanotubes as adsorbent for the removal of manganese from aqueous solution

A batch adsorption process was applied to investigate the removal of manganese from aqueous solution by oxidized multiwalled carbon nanotubes (MWCNTs). In doing so, the thermodynamic, adsorption isotherm, and kinetic studies were also carried out. MWCNT with 5–10-nm outer diameter, surface area of 40–600 m²/g, and purity above 95 % was used as an adsorbent. A systematic study of the adsorption process was performed by varying pH, ionic strength, and temperature. Manganese-adsorbed MWCNT was characterized by Raman, FTIR, X-ray diffraction, XPS, SEM, and TEM. The adsorption efficiency could reach 96.82 %, suggesting that MWCNT is an excellent adsorbent for manganese removal from water. The results indicate that second-order kinetics model was well suitable to model the kinetic adsorption of manganese. Equilibrium data were well described by the typical Langmuir adsorption isotherm. Thermodynamic studies revealed that the adsorption reaction was spontaneous and endothermic process. The experimental results showed that MWCNT is an excellent manganese adsorbent. The MWCNTs removed the manganese present in the water and reduced it to a permissible level making it drinkable.