天然沸石对农田退水中氨氮的去除

利用静态吸附实验研究了沸石颗粒大小、氨氮初始浓度、接触时间及Na+离子浓度等因素对天然白银沸石去除模拟黄灌区农田退水中氨氮(NH4+-N)效果的影响,同时研究了吸附等温线特征,并考察了其吸附机理.研究结果表明,沸石颗粒大小、接触时间及NH4+和Na+初始浓度对NH4+-N交换容量都会产生一定影响;根据复相关系数(R2),NH4+-N的吸附等温线更符合三参数等温线模型;而对于两参数等温线模型,Langmuir模型比Freundlich模型能更好地描述NH4+-N在天然沸石上的离子交换过程;NH4+-N吸附实验数据与Elovich模型拟合最好(R2≥0.9766).研究结果表明了天然白银沸石是一种适合NH4+-N去除的离子交换剂,可用于黄灌区农田退水中NH4+-N的去除.     

两种盐复合改性活性氧化铝对水中氟的吸附特性

采用Fe2(SO4)3和Al2(SO4)3两种盐对活性氧化铝进行改性,通过静态吸附实验,研究了改性活性氧化铝对水中氟离子的吸附特性及影响因素.改性后的活性氧化铝吸附容量显著提高,25℃下吸附容量达到6.25 mg·g-1.改性活性氧化铝对氟的吸附动力学符合拟二级动力学模型,吸附等温线更符合Langmuir等温吸附规律.吸附过程ΔG0<0、ΔH0>0、ΔS0>0,表明改性吸附剂对氟的吸附是自发的,是吸热、熵增加的反应.吸附最佳p H值为6,吸附过程中,共存PO3-4对吸附效果影响最大.     

有机沸石对水中BTEX及铬酸根离子的吸附

以天然沸石作为对比物 ,考察了有机沸石对水中BTEX (苯、甲苯、乙苯、二甲苯 )及铬酸根离子的吸附性能 .结果表明 :有机沸石对水中BTEX和铬酸根离子的吸附性能较天然沸石有了很大提高 ,在低质量浓度范围 ( 0— 0 2 5g·l- 1 )内呈现良好的线性关系 .对铬酸根离子的吸附符合Langmuir吸附模型 ,1 5℃时的饱和吸附容量为 1 5 97g·kg- 1 .     

苯胺-2,4-二氨基酚共聚物吸附水中Hg(Ⅱ)的动力学和热力学研究

利用化学氧化法合成苯胺-2,4-二氨基酚共聚物,通过静态吸附实验研究了该共聚物吸附水中汞离子的动力学和热力学.对实验数据采用准一级和准二级动力学方程、Langmuir等温线方程、Freundlich等温线方程进行拟合,并进行相应的热力学分析.研究结果表明,苯胺-2,4-二氨基酚共聚物对水中Hg(Ⅱ)具有很好的去除效果,最大吸附容量达800mg·g-1,吸附等温线符合Langmuir单层吸附模型;动力学过程符合准二级动力学模型;吸附焓变化量ΔH=58.51kJ·mol-1,表明该吸附反应为化学吸附且为吸热反应;三种实验温度下吉布斯自由能变化量均为负值,表明该吸附反应能自发进行。     

废弃茶叶吸附剂去除水中的氟离子

地热温泉常含有高浓度的氟,给温泉利用带来不可忽视的环境问题,因此温泉水中氟离子吸附净化处理是重要的研究热点.本文采用废弃茶叶作为吸附剂,氟离子为目标离子,优化了茶叶吸附剂种类、溶液pH对吸附效果的影响.在pH 3、初始浓度为5 mg·L^-1时,大红袍茶叶对氟离子的吸附容量达到0.126 mg·g^-1.进一步考察了吸附剂对氟离子的吸附机制,结果表明,氟离子吸附符合Pseudo-secondorder动力学模型,等温线符合Freundlich模型,氟离子吸附过程主要通过与茶叶中的羟基和羧基活性基团发生交换作用.茶叶氟吸附量虽较其它天然吸附剂略低但无需复杂改性和前处理,具有环境友好,成本低廉,来源丰富,易与获得等优点,在含氟水净化处理具有潜在应用和发展前景.     

改性斜发沸石处理高浓度氨氮废水

采用NaOH碱熔法对缙云斜发沸石进行处理,采用正交实验对碱熔法改性沸石的最佳条件进行了选择;并对改性前后的沸石进行粉末X射线衍射(XRD)、电感耦合等离子体发射光谱法(ICP-AES)和扫描电镜(SEM)表征;详细研究了所得改性沸石在氨氮废水处理中的净化性能.结果表明,处理沸石的水热温度对氨氮去除效果的影响最显著;碱熔法处理可使缙云斜发沸石转变为低硅铝比的Na-P型分子筛,它对氨氮废水的NH4+-N具有优异的吸附性能.当改性沸石投加量为5 g,对100 mL浓度为1000 mg.L-1氨氮溶液,氨氮去除率可达77.8%,改性沸石吸附NH4+-N是一快速吸附过程,且能较好地符合Langmuir吸附等温模式,偏向于单分子层的吸附.     

伊利石对水溶液中低浓度铀的吸附

采用静态实验方法研究了伊利石对水溶液中铀的吸附特性,通过批实验考察了反应时间、溶液初始浓度、p H值、离子强度、固液比以及温度对吸附的影响,用傅里叶变换红外光谱仪(FTIR)、X射线衍射仪(XRD)表征伊利石吸附铀前后结构的变化,探讨了伊利石对铀的吸附等温方程和热力学规律,分析其反应机制.实验结果显示,伊利石与低浓度铀溶液接触后立即反应,1 h后反应基本达到平衡;溶液p H和离子强度对伊利石吸附铀的影响显著,当p H=4—7、离子强度为0.001 mol·L-1时,吸附效果最好;在一定条件下,伊利石对水溶液中低浓度铀的吸附量与铀初始浓度呈正比,与固液比呈反比;吸附等温线符合Freundlich模型,相关系数可达0.9966;伊利石对铀的吸附属于吸热反应,反应自发进行,高温促进伊利石的吸附行为.     

含水层介质对氯酚类污染物的吸附-解吸特性

为探讨含水层介质对氯酚类污染物的吸附规律,以吉林市含水层介质--砂土为实验材料,采用批量吸附实验方法分别研究了2,4-二氯酚、2,4,6-三氯酚及五氯酚单独存在和共存条件下在砂土上的吸附-解吸行为,并对pH、离子强度对吸附过程的影响进行了探讨.结果表明,砂土对三种氯酚的吸附-解吸符合Freundlieh等温模型,吸附常数Kd分别为5.659、2.507和2.104,解吸常数分别为22.642、8.222和4.488;吸附反应符合二级吸附速率动力学方程,吸附速率常数K分别为0.4851 kg·mg-1·h-1、0.0299 kg·mg-1·h-1和0.1225 kg·mg-1·h-1.氯酚在砂土上的吸附机理以疏水分配和配位体交换为主.在实验范围值内,吸附量随pH增加而减小,增加离子强度可以明显加强氯酚在砂土上的吸附.     

磺酸基改性磁性吸附剂去除水中的Cu(Ⅱ)

利用水热法制备出Fe_3O_4磁性粒子,通过正硅酸乙酯水解使Fe_3O_4外面包覆SiO_2(Fe_3O_4@SiO_2),最后利用3-氨丙基三甲氧基硅烷和氯磺酸进行改性,合成了磺酸基改性磁性吸附剂.采用FT-IR、BET和XRD等方法对合成吸附剂进行表征,并探讨接触时间、初始浓度、溶液pH值等因素对吸附性能的影响.表征结果显示,成功合成了磺酸基改性磁性Fe_3O_4@SiO_2粒子;Fe_3O_4@SO_3Na比表面积为20.4587 m~(-2)·g~(-1).吸附实验结果显示,在25℃条件下,Fe_3O_4@SO_3Na对Cu~(2+)的吸附等温线符合Freundlich吸附等温方程,实验条件下最大吸附量为16.13 mg·g~(-1).Fe_3O_4@SO_3Na吸附Cu~(2+)可在1 h内达到吸附平衡且吸附动力学遵循拟二级动力学模型.溶液中存在盐离子时,发现盐离子的存在对吸附效果几乎没有影响;溶液中含有柠檬酸时对吸附效果产生抑制.吸附剂经3次循环使用后仍有吸附性能,表明吸附剂具有良好的再生性和经济性.     

生物吸附剂-海黍子吸附镍

采用生物吸附剂-海黍子对重金属镍离子进行吸附，做了动力学实验，得到了海黍子吸附镍的动力学方程。研究了溶液的pH值，初始Ni^2 浓度等因素对Ni^2 的吸附特性的影响，得到最佳pH值4～6及最大吸附量0．8283mmo1／g，并用Langmuir和Freundlich方程对吸附等温线进行了拟合，用Langmuir方程拟合相关系数R^2达0．999以上。     

NKA—Ⅱ大孔吸附树脂吸附高浓度苯胺溶液的试验研究

本文利用ＮＫＡ－Ⅱ大孔吸附树脂对高浓度苯胺溶液进行了静态吸附试验,希望利用大孔吸附树脂从化工废水中回收苯胺。     

改性泥炭对水溶液中铬的去除

为克服泥炭利用过程中存在的一些问题，对原泥炭进行了改性处理，并将改性后的泥炭与树脂结合以增强改性泥炭的机械强度。通过静态试验方法研究了改性泥炭对来自水溶液中的铬离子的吸附特性。结果表明：改性泥炭对水溶液中的铬的吸附等温过程符合Freundlich吸附等温方程，其吸附动力学符合准二级动力学方程。溶液的pH值对铬的去除产生显著的影响，在pH在1．5－3．0时，改性泥炭对6价铬的去除效果最好。     

Biosorption of Cr(VI) from wastewater using Sorghastrum Nutans L. Nash

Sorghastrum Nutans L. Nash is used as an adsorbent for the removal of Cr(VI) from wastewater. Adsorption coupled reduction i.e. indirect reduction is the mechanism of Cr(VI) removal by the biomaterial. The adsorbent surface became highly positively charged at lower pH, adsorption rate of Cr(VI) is faster and reduction reaction also accelerates at lower pH since the binding of negatively charged Cr(VI) ion species to the cationic groups is enhanced and protons take part in this reaction. The adsorbent is characterised by using XRD, FTIR, SEM and EDAX analysis. OH bending, CN stretching/bending and NH stretching play a major role in Chromium adsorption. Experimental values follow pseudo-second order reaction and Langmuir adsorption isotherm. Surface diffusion is the rate controlling mechanism for the process. The maximum percentage of Cr(VI) removal obtained is 75.5% with 7?g/L dosage at pH 1.3 and adsorbate concentration was 100?mg/L. From the normal probability, residual, contour, 3D surface, main effect and interaction plot along with t-test, ANOVA, and F-test, it is observed that pH has the most significant effect on the percentage removal followed by adsorbent dosage and time. The adsorbate concentration has the least effects and interaction effects are found to be significant.     

吸附模式对有机物光催化降解的影响1.H-酸在TiO2表面的吸附模式

H-酸萘环上含有的两个磺酸基团,在水溶液中可以解离一个或者两个.pH 2.5条件下,主要有一个磺酸基团解离,此时,H-酸通过一个磺酸基团吸附在TiO2表面,占位小,饱和吸附量大,但吸附键较弱,吸附较可逆.pH 5.0条件下,主要有两个磺酸基团解离,此时,H-酸通过两个磺酸基团吸附在TiO2表面,占位大,饱和吸附量小,但吸附键较强,吸附不可逆性较强.这种吸附模式的差异是导致H-酸在不同pH条件下饱和吸附量和吸附不可逆性差异的根本原因,也是导致不同pH条件下H-酸具有不同光催化降解途径的重要原因.     

胺型腰果酚醛树脂对Ag~+的吸附

制备了3种胺型腰果酚醛树脂(二乙撑三胺型腰果酚醛树脂(PCD)、己二胺型腰果酚醛树脂(PCE)、己二胺型腰果酚醛树脂(PCH)),采用XPS(X-射线光电子能谱仪)、EA(元素分析仪)、FTIR(傅利叶变换红外光谱分析仪)等手段研究了其结构特征,并考察了其对水溶液中Ag+的吸附行为和机理.结果表明,3种树脂对Ag+有较高的吸附量和吸附作用;在pH值为5.5的条件下,树脂对Ag+的吸附效果最佳;2h内吸附达到平衡;吸附行为均符合Lagergren准二级速率方程;树脂对Ag+的吸附均符合Langmuir等温吸附方程;吸附反应为自发吸热和熵增的过程;可溶性无机盐对树脂吸附Ag+的影响不大;推测其吸附机理是树脂上胺基、羟基与Ag+发生较强的配位作用和较弱的离子交换作用的化学吸附为主.吸附Ag+后的树脂可用硝酸脱附再生;树脂循环使用4次后,吸附率和脱附率仍大于90%.     

Kinetic and equilibrium study of Alizarin Red S removal by activated carbon

Activated carbon has been applied for the adsorption of Alizarin Red S (ARS) from the waste water in a batch method to obtain high removal percentage. The influence of variables such as pH, temperature, ARS concentration, mass and size of adsorbent, and contact time on ARS removal percentage was investigated. Different kinetics, thermodynamics, and isotherm models were applied for fitting the experimental data. The adsorption process follows a pseudo second-order kinetic model with R ² of 0.98 and Freundlich, Tempkin, and Dubinin-Radushkevich isotherm models with high determination coefficients (R ²) of 0.91, 0.98, and 0.98, respectively. High enthalpy (positive value), Gibbs free energy (negative value), and high entropy values shows the feasibility and the endothermic spontaneous nature of the removal process.     

Adsorption of sulfonamides on lake sediments

Sulfonamides (SAs) are one class of the most widely used antibiotics around the world. Their fate and transport in the aquatic environment is of great concern. In this study, adsorption of four SAs—sulfadiazine (SD), sulfamethoxazole (SMZ), sulfadimethoxine (SDM) and sulfamethazine (SM2)—in single-solute and multi-solute systems on sediments of Dianchi (DC) Lake and Taihu (TH) Lake, China was investigated with batch experiments. In the single-solute adsorption system, the Langmuir model and the dual-mode model described the adsorption process better than the Freundlich model. Model fitness was better on DC sediment than on TH sediment. The order of adsorption capacity approximately followed a decreasing order of SDM>SD>SM2>SMZ on both sediments, which was likely attributed to the distinctly different water solubility of the four SAs. In the multi-solute system, the order of adsorption capacity was SM2>SDM>SD>SMZ, which was probably related to the compound speciation caused by the pH values of the experimental solution. In the multi-solute system, both competitive and cooperative adsorption played important roles in the adsorption of sulfonamides on sediments.     

银在活性炭上的吸附行为和机理的研究

本文研究了银在活性炭上的吸附行为，探讨了影响吸附效率的各种因素。考察了多种溶液对吸附银的洗脱效果，发现银在活性炭上的吸附不是还原吸附，而是以离子形成与活性炭表面的－ＮＨ２和＝ＮＨ形成络合物而被吸附。     

杭锦2~#土复合吸附剂对磷的吸附动力学

通过静态试验考察杭锦2#土/聚合硫酸铝复合吸附剂对生活污水中磷酸根的吸附特性,研究吸附过程的动力学模型,并从动力学角度探讨其吸附机理。结果表明,在杭锦2#土/聚合硫酸铝复合吸附剂用量5 g.L-1、吸附时间60 min、废水pH值6.0、温度25℃、磷初始质量浓度小于16.72 mg.L-1条件下,磷酸根的去除率在96%以上;复合吸附剂对磷酸根的吸附动力学特征符合假二级方程,吸附速率在前10 min为内扩散控制,后期由膜扩散和内扩散共同控制,且膜扩散占主导地位;磷酸根的初始浓度越高,吸附质粒子的表观内扩散系数和表观传质系数越小;使用不同再生次数的再生吸附剂（添加量为5 g.L-1）处理16.72 mg.L-1含磷生活污水,随着再生次数的增加,吸附能力有所下降,但磷酸根的去除率均大于89%。     

Adsorptive removal of mercury from acid mine drainage: a comparison of silica and maghemite nanoparticles

Mercury adsorption by silica and maghemite nanoparticles (NPs) was studied with the aim of comparing their performance in the remediation of acid mine drainage (AMD) contaminated water. Calculated distribution coefficients (K_d) showed that both NPs are exceptional adsorbents. However, adsorbate coverage per unit area was 30 times higher for maghemite than for silica NPs, despite the latter having a surface area ～15 times greater. Maghemite adsorbed 75% of available Hg compared to 56% by silica, making it a more efficient sorbent than silica under AMD conditions. Kinetics and isotherm data for both adsorbents were fitted by the pseudo-second-order (R² = 1) and the Freundlich (R² ≥ 0.98) models, implying that adsorption to both NP types was by chemisorption. Adsorption increased with NP concentrations and pH and was enhanced in the presence of manganese and sulfate ions although adsorption to silica was inhibited in 1:2 Hg-to-Mn systems. Importantly, trends in simulated wastewater were replicated in actual AMD-contaminated water samples. This study highlights the fact that properties besides surface area and charge of adsorbents determine adsorbent performance, and superior attributes may not always lead to higher adsorption efficiencies.