改性硅藻土对富营养化水体中磷的吸附行为

以硅藻土原土为原料,通过碱洗及浸渍负载羟基氧化铁对其进行改性,利用SEM、XRD及物理吸附仪对改性硅藻土的形貌、比表面积等进行表征,并研究了改性硅藻土对富营养化水体中磷的吸附性能。结果表明,(1)改性后,硅藻土杂质元素减少,孔径明显增大,比表面积增大23倍,并有效负载了β-FeO(OH);(2)其对磷的吸附受温度及pH值的影响,温度越高,达到吸附平衡时间越短,吸附容量也越大;在pH值为4~11之间,吸附容量随pH的增大而减小;(3)拟二级反应动力学方程,能准确地描述改性硅藻土对磷的吸附,而粒内扩散,不是改性硅藻土对磷吸附的唯一控制步骤;(4)改性硅藻土在富营养化水体中对磷的吸附行为,符合Freundlich等温线方程,其吸附过程为物理吸附,吸附过程焓变(H)为39.949kJ/mol,各温度下的自由能变(G)均小于零,熵变(S)均为正值,该吸附过程是自发的吸热物理过程。     

氨氮与磷在三种人工湿地填料上的吸附动力学

利用吸附动力学实验研究了浮石、陶结和陶粒对氨氮和磷的吸附动力学特征.结果表明:浮石对氨氮与磷的吸附容量明显比陶结和陶粒的大.人工湿地填料浮石和陶粒对氨氮与磷,以及陶结对氨氮的等温吸附动力学特征均可以用准一级、准二级和Bangham模型加以描述.其中浮石对氨氮和磷以及陶结对氨氮的吸附以化学吸附反应控制为主,而陶粒对磷的吸附过程则以扩散反应控制为主.三种填料对氨氮和磷的吸附均以表面吸附为主.     

聚硫醚纤维素吸附阳离子染料的动力学与热力学

脱脂棉在碱存在下与环硫氯丙烷发生醚化反应,合成了一种环境功能材料--聚硫醚纤维素（PTCC）。 考察了溶液酸度对吸附容量的影响并研究了PTCC对3种阳离子染料的吸附动力学与热力学。 研究结果表明,中性介质较有利于吸附的进行;298 K、pH=7.0时,静态吸附2 h后,吸附趋于平衡,PTCC对碱性艳蓝B、碱性艳蓝R和夜蓝的饱和吸附量分别为726、652和320 mg/g;PTCC对阳离子染料的吸附过程符合Lagergren二级吸附动力学方程,吸附速率常数k2随着温度的降低而升高,低温有利于吸附反应的进行;吸附过程ΔG、ΔH和ΔS均为负值,表明该吸附是自发的放热过程,主要是通过范德华力实现的。 吸附过程的吸附等温模型符合Langmuir等温式,可以用单分子层吸附理论加以解释。     

水杨酸型螯合树脂对Fe(III)离子的螯合吸附行为

以5-氨基水杨酸(ASA)为胺化试剂, 使氯甲基化的交联聚苯乙烯(CMCPS)微球表面的苄氯基团发生亲核取代反应, 制得了水杨酸型螯合树脂ASA-CPS. 研究了该螯合树脂对金属离子的螯合吸附行为, 探讨了其吸附热力学与吸附机理, 考察了介质pH值对树脂螯合吸附性能的影响以及树脂对不同金属离子的螯合吸附能力. 实验结果表明, 水杨酸型螯合树脂ASA-CPS 对重金属离子具有强螯合吸附性能, 尤其对Fe3+离子表现出很强的螯合吸附能力, 常温下吸附容量可达21 g/100 g. 吸附过程属熵驱动的化学吸附过程, 升高温度, 吸附容量增高; 在可抑制金属离子水解的pH范围内, 介质的pH值越高, 螯合吸附能力越强; 对于性质不同的金属离子, ASA-CPS的吸附性能是有差别的, 吸附容量的顺序为Fe3+>Ni2+>Cu2+>Zn2+.     

钾位铈掺杂黄钾铁矾的磷吸附特性及机理研究※

黄钾铁矾是一种自然界常见的含铁矿物, 它对砷酸根有一定吸附作用, 但几乎不吸附同样构型的磷酸根. 为了改善黄钾铁矾的磷吸附性质, 本研究制备了铈掺杂的黄钾铁矾, 并采用X射线衍射(XRD)、电感耦合等离子发射光谱(ICP-OES)等表征手段, 构建了铈离子占据钾离子位的结构模型. 磷吸附实验结果表明, 少量铈的掺杂可将黄钾铁矾的磷吸附容量(pH=7, 24 h)从1.69 mg/g显著提升至29.33 mg/g. 同时, 初始pH和共存阴离子对其除磷效果影响较小, 说明含铈黄钾铁矾对磷酸盐的吸附具备高选择性. 进一步分析表明, 该吸附过程符合准二级动力学模型, 吸附等温线符合Freundlich等温吸附模型, 分析结果表明吸附过程可能是易进行的化学吸附. 利用XRD及阴离子交换色谱, 证实了相比于纯黄钾铁矾, 铈的掺杂提高了黄钾铁矾的反应活性, 大幅提升了吸附过程中磷酸根与硫酸根的置换. 通过X射线光电子能谱与红外光谱表征, 推测吸附过程形成稳定的Ce—O—P化学键, 实现特异性化学吸附. 这些研究结果为含磷废水的吸附治理提供了一种新的吸附材料, 并有望为黄钾铁矾的改性和资源化利用提供参考.     

纳米TiO2分离富集Mo(Ⅵ)和Re(Ⅶ)

本文研究了纳米TiO2吸附剂对Mo(VI)、Re(VII)的吸附行为,考察了溶液的pH值、吸附时间、温度等因素对吸附的影响。结果表明：纳米TiO2对Mo(VI)的吸附在pH 1～8条件下,吸附率超过99%,2 mL 0.05mol/L NaOH溶液可将吸附的Mo(VI)离子完全洗脱,解吸率能达到97%。在pH 1～10范围内,纳米TiO2不吸附Re(VII), 从而达到Mo(VI)、Re(VII)分离。在2℃～50℃温度范围内,Mo(VI)的吸附过程符合Langmiur等温式,纳米TiO2对Mo(VI)的最大吸附容量从11.51mg g-1增加到14.19 mg g-1;纳米TiO2分离钼后,溶液剩余的铼,用活性炭吸附,在pH1～10范围内, Re(VII)的吸附率可达99%,用浓氨水进行洗脱,洗脱率可达96%;吸附过程可用准二级反应动力学模型描述,是以化学吸附为控制步骤的吸附过程;吸附等温线与Freundlich模型有较好的拟合。     

功能化介孔硅分子筛吸附剂除磷性能的研究

分别在甲基二甲氧基硅烷改性介孔分子筛MCM41上锚定Al和Fe离子,成功制备了功能化的介孔硅分子筛有机/无机杂化吸附剂Al-NN-MCM41和Fe-NN-MCM41。详细考察了磷溶液初始浓度、吸附时间,溶液pH值和共存离子等对吸附剂磷吸附性能的影响。实验结果表明:Langmiur等温方程比Freundlich等温方程能更好地描述磷酸根离子在两种吸附剂上的吸附,两种吸附剂的吸附动力学过程更适合动力学准二级方程(r20.99)。磷溶液的pH值对吸附剂的磷吸附容量有显著影响。此外,同时添加NO33-、Cl-、SO42-、CO32-四种共存离子对吸附剂磷吸附效率没有显著影响。     

水杨酸型螯合树脂对Fe（Ⅲ）离子的螯合吸附行为

以5-氨基水杨酸(ASA)为胺化试剂,使氯甲基化的交联聚苯乙烯(CMCPS)微球表面的苄氯基团发生亲核取代反应,制得了水杨酸型螯合树脂ASA-CPS.研究了该螯合树脂对金属离子的螯合吸附行为,探讨了其吸附热力学与吸附机理,考察了介质pH值对树脂螯合吸附性能的影响以及树脂对不同金属离子的螯合吸附能力.实验结果表明,水杨酸型螯合树脂ASA-CPS对重金属离子具有强螫合吸附性能,尤其对Fe3+子表现出很强的螯合吸附能力,常温下吸附容量可达21 g/100 g.吸附过程属熵驱动的化学吸附过程,升高温度,吸附容量增高;在可抑制金属离子水解的pH范围内,介质的pH值越高,螯合吸附能力越强;对于性质不同的金属离子,ASA-CPS的吸附性能是有差别的,吸附容量的顺序为Fe3+>Ni2+>Cu2+>Zn>3+     

刷状结构的阳离子性接枝微粒QPDMAEMA/SiO2对牛血清白蛋白的吸附特性

以微米级硅胶微粒为基质, 通过接枝聚合和大分子反应, 制备了具有刷状结构的阳离子性接枝微粒, 深入研究了其对牛血清白蛋白(BSA)的强吸附能力、吸附机理和吸附热力学. 首先使含叔胺基团的单体甲基丙烯酸二甲基氨基乙酯(DMAEMA)在硅胶微粒表面发生接枝聚合, 制得接枝微粒PDMAEMA/SiO₂, 然后以氯乙胺为试剂, 使接枝大分子PDMAEMA链中的叔胺基团发生季铵化反应, 获得了具有刷状结构的阳离子聚电解质的功能接枝微粒QPDMAEMA/SiO₂. 测定了微粒QPDMAEMA/SiO₂的zeta 电位, 实施了对BSA的等温吸附实验, 考察了介质pH值、离子强度及温度对吸附作用的影响, 研究了吸附热力学. 研究结果表明, 功能接枝微粒QPDMAEMA/SiO₂ 比接枝微粒PDMAEMA/SiO₂ 具有更高的zeta 电位, 在静电相互作用驱动下, 微粒QPDMAEMA/SiO₂对BSA具有很强的吸附能力. 吸附容量随介质pH值的增大呈现先增大后减小的变化趋势,当pH值等于BSA的等电点(pI=4.7)时, 具有最高的吸附容量(高达112 mg·g^-1). 以等电点为界, 离子强度对吸附容量会产生完全相反的影响作用: 当介质pH值小于BSA的等电点时, 电解质浓度增大, 吸附容量增高; 当介质pH值等于BSA的等电点时, 吸附容量几乎不随电解质的浓度发生变化. 吸附过程熵值减小而且放出热量,是一个焓驱动的吸附过程.     

亚氨二乙酸型复合材料IDAA-PGMA/SiO2对重金属及稀土离子的吸附行为与吸附热力学

将甲基丙烯酸缩水甘油酯(GMA)接枝于硅胶微粒表面,制得了接枝微粒PGMA/SiO₂; 使亚氨二乙酸(IDAA)与接枝PGMA的环氧基团发生开环反应, 从而将亚氨二乙酸基团引入接枝微粒表面, 制得了复合螯合微粒材料IDAA-PGMA/SiO₂. 本文研究了IDAA-PGMA/SiO₂对重金属及稀土离子的螯合吸附行为, 深入地研究了吸附机理与吸附热力学. 研究结果表明: 凭借亚氨二乙酸基团与重金属离子之间的静电作用与配位螯合作用的协同, 复合微粒材料IDAA-PGMA/SiO₂对重金属离子可产生强的螯合吸附作用, 尤其对Pb²⁺离子表现出很强的螯合吸附能力, 常温下吸附容量可达0.235 g·g^-1; IDAA-PGMA/SiO₂对重金属离子的吸附过程为一放热过程, 且为焓驱动的过程, 升高温度, 吸附容量降低; 对稀土离子的吸附过程则为熵驱动的过程; 在可抑制金属离子水解的pH范围内, 介质的pH值越高, IDAA-PGMA/SiO₂的螯合吸附能力越强; IDAA-PGMA/SiO₂对重金属离子的吸附容量远高于对稀土离子的吸附容量.     

Adsorption of phosphate and nitrate anions on ammonium-functionalized MCM-48: effects of experimental conditions

In this study, ammonium-functionalized MCM-48 (Mobil Composite Material No. 48) was used as an adsorbent to remove nitrate (NO(-)(3)) and monobasic phosphate (H(2)PO(-)(4)) anions from aqueous solutions. The effects of operating conditions such as temperature, adsorbent loading, initial anion concentration, pH, and the presence of competitive ions on the adsorption performances were examined. Results showed that adsorption capacity decreased with increasing temperature. The adsorption capacity increased with adsorbent loading and initial anion concentration. The removal of nitrate was maximum at pH<8, while phosphate removal was maximized at pH 5. The adsorption was almost unaffected by the presence of competitive ions in the case of phosphate anions. However, their presence adversely affected nitrate adsorption. Desorption of both anions was rapidly achieved within 10 min using NaOH at 0.01 M. Regeneration tests showed that the adsorbent retained its capacity after 5 adsorption-desorption cycles.     

单宁微球对牛血清蛋白的吸附

采用反相悬浮聚合法制备单宁微球,利用扫描电子显微镜对微球的表面形貌进行观察.同时以单宁微球为吸附剂,探讨pH值、单宁微球质量、牛血清蛋白起始浓度、吸附时间等条件对单宁微球吸附牛血清蛋白性能的影响,得出单宁微球吸附牛血清蛋白的最佳条件.并用两种动力学模型进行拟合.结果表明,单宁微球对牛血清蛋白的吸附速率先快后慢,最后吸附...     

碳纳米管负载氧化铝材料的制备及其吸附水中氟离子的研究

采用碳纳米管和硝酸铝制备了碳纳米管负载氧化铝新型除氟材料.X射线衍射检测发现,当焙烧温度低于850℃时,氧化铝为无定形态,当焙烧温度为1050℃时,氧化铝为α形态,扫描电子显微镜观察到碳纳米管与氧化铝均匀掺杂.同时用碳纳米管负载氧化铝复合材料进行水中氟离子的吸附研究,结果表明,该复合材料具有优良的除氟效能.氧化铝负载量为30%、焙烧温度为450℃条件下制备的碳纳米管负载氧化铝复合材料的吸附除氟能力是γ-氧化铝的2.0～3.5倍,与IRA-410聚合树脂的吸附除氟能力相当,适宜pH范围为5.0～9.0,吸附等温线符合Freundlich方程.     

New inorganic (an)ion exchangers based on Mg-Al hydrous oxides: (alkoxide-free) sol-gel synthesis and characterisation

New inorganic ion exchangers based on double Mg-Al hydrous oxides were generated via the new non-traditional sol-gel synthesis method which avoids using metal alkoxides as raw materials. Surface chemical and adsorptive properties of the final products were controlled by several ways of hydrogels and xerogels treatments which produced the materials of the layered structure, mixed hydrous oxides or amorphous adsorbents. The final adsorptive materials obtained via thermal treatment of xerogels were the layered mesoporous materials with carbonate in the interlayer space, surface abundance with hydroxylic groups and maximum adsorptive capacity to arsenate. Higher affinity of Mg-Al hydrous oxides towards H(2)AsO(4)(-) is confirmed by steep adsorption isotherms having plateau (removal capacity) at 220 mg[As]g(dw)(-1) for the best sample at pH=7, fast adsorption kinetics and little pH effect. Adsorption of arsenite, fluoride, bromate, bromide, selenate, borate by Mg-Al hydrous oxides was few times high either competitive (depending on the anion) as compare with the conventional inorganic ion exchange adsorbents.     

Preparation and adsorption properties of monodisperse chitosan-bound Fe3O4 magnetic nanoparticles for removal of Cu(II) ions

Monodisperse chitosan-bound Fe(3)O(4) nanoparticles were developed as a novel magnetic nano-adsorbent for the removal of heavy metal ions. Chitosan was first carboxymethylated and then covalently bound on the surface of Fe(3)O(4) nanoparticles via carbodiimide activation. Transmission electron microscopy micrographs showed that the chitosan-bound Fe(3)O(4) nanoparticles were monodisperse and had a mean diameter of 13.5 nm. X-ray diffraction patterns indicated that the magnetic nanoparticles were pure Fe(3)O(4) with a spinel structure, and the binding of chitosan did not result in a phase change. The binding of chitosan was also demonstrated by the measurement of zeta potential, and the weight percentage of chitosan bound to Fe(3)O(4) nanoparticles was estimated to be about 4.92 wt%. The chitosan-bound Fe(3)O(4) nanoparticles were shown to be quite efficient for the removal of Cu(II) ions at pH>2. In particular, the adsorption rate was so fast that the equilibrium was achieved within 1 min due to the absence of internal diffusion resistance. The adsorption data obeyed the Langmuir equation with a maximum adsorption capacity of 21.5 mg g(-1) and a Langmuir adsorption equilibrium constant of 0.0165 L mg(-1). The pH and temperature effects revealed that the adsorption capacity increased significantly with increasing pH at pH 2-5, and the adsorption process was exothermic in nature with an enthalpy change of -6.14 kJ mol(-1) at 300-330 K.     

纯相钙铝层状双氢氧化物对磷的吸附特性

采用乙醇辅助液相共沉淀法制备了纯相Ca-Al-LDH层状双金属氢氧化物,考察了Ca-Al-LDH的投加量、吸附时间、pH值、无机电解质(Na₂CO₃ ,KCl ,Na₂SO₄,KNO₃)和温度等因素对磷吸附的影响,结果表明,纯相Ca-Al-LDH对磷酸根离子具有很好的吸附性能,最大饱和吸附量可达160.78 mg/g,当pH值为5.1、温度为45 ℃、吸附时间为600 min、LDH投加量为0.6 g/L、磷初始浓度为80 mg/L时,磷的去除率高达95.88%;无机阴离子会抑制磷在吸附剂上的吸附,当Cl^-浓度从2.5 g/L升高到25 g/L时,Ca-Al-LDH对磷酸盐的最大饱和吸附量从69.96 mg/g降至53.18 mg/g,降低了23.99%;当SO₄^2-浓度从2.5 g/L升高到25 g/L时,Ca-Al-LDH对磷酸盐的最大饱和吸附量降低了24.79%,其它无机阴离子对磷在吸附剂上的吸附也有一定的影响。 Ca-Al-LDH对水中磷的吸附符合二级动力学方程和Langmuir等温模型。 采用扫描电子显微镜、傅里叶变换红外光谱仪和X射线衍射仪等技术手段对制备的纯相Ca-Al-LDH及其吸附磷酸根后的产物进行表征,揭示了Ca-Al-LDH对磷酸根的吸附可能是静电吸引、化学吸附和阴离子插层等过程协同作用的吸附机理。     

Equilibrium and kinetic studies of adsorption of phosphate onto ZnCl2 activated coir pith carbon

Phosphate removal from aqueous solution was investigated using ZnCl₂-activated carbon developed from coir pith, an agricultural solid waste. Studies were conducted to delineate the effect of contact time, adsorbent dose, phosphate concentration, pH, and temperature. The adsorption equilibrium data followed both Langmuir and Freundlich isotherms. Langmuir adsorption capacity was found to be 5.1 mg/g. Adsorption followed second-order kinetics. The removal was maximum in the pH range 3–10. pH effect and desorption studies showed that adsorption occurred by both ion exchange and chemisorption mechanisms. Adsorption was found to be spontaneous and endothermic. Effect of foreign ions on adsorption shows that perchlorate, sulfate, and selenite decreased the percent removal of phosphate.     

Increasing the arsenate adsorption capacity of neutralized red mud (Bauxsol)

The possibility of increasing the arsenate adsorption capacity of seawater-neutralized red mud (Bauxsol) through acid treatment, combined acid and heat treatment, and the addition of ferric sulfate (Fe(2)(SO(4))(3).7H(2)O) or aluminum sulfate (Al(2)(SO(4))(3). 18H(2)O) is investigated. The results show that acid treatment alone, as well as in combination with heat treatment increases the removal efficiency, with the combination providing the best removal. Adding ferric sulfate or aluminum sulfate, however, suppress the removal. The results also show that activated Bauxsol (AB) produced using combined acid and heat treatment can remove roughly 100% arsenate (at pH 4.5) with or without competing anions (i.e., phosphate, bicarbonate, and sulfate) when the initial arsenate concentration is < or = 2 mgl(-1). Furthermore, it is found that the adsorption process using AB is not accompanied by the release of unwanted contaminants, and TCLP results indicate that the spent AB is not hazardous. It is believed that the AB produced here has good potential as an alternative adsorbent to conventional methods for removing arsenate from water.     

介孔硅胶在柴油氧化-吸附组合脱硫中的应用研究

以硅胶(SG)为吸附剂,采用自制的双亲催化剂与H₂O₂组成的催化氧化体系将柴油进行氧化,利用固定床动态吸附法考察了硅胶性质、氧化过程及吸附条件等对硅胶吸附脱硫性能的影响,并对硅胶进行了表征。小角XRD和氮气吸脱附结果表明,实验所用硅胶具有介孔结构。吸附脱硫实验结果表明,在油剂比(柴油与吸附剂的体积比)相同时,氧化-吸附脱硫过程脱硫率明显高于吸附脱硫过程脱硫率;选用硅胶作吸附剂,吸附温度为40℃,吸附空速为6.0 h^-1时脱硫效果较好,当油剂比为1时,脱硫率高达94.57%,且该介孔硅胶具有较大的吸附硫容,随油剂比增大下降缓慢,当油剂比增大到15时,脱硫率仍达85.89%。     

Kinetics and Thermodynamics of the Adsorption of Copper(Ⅱ) onto a New Fe-Si Adsorbent

A new kind of Fe-Si adsorbent was synthesized by iron oxide and diatomite after calcining and hydrothermal process. The influences of the initial Cu2+ concentration, p H and adsorption time on the Cu2+ removal efficiency were discussed. Three adsorption empirical kinetics equations and two thermodynamics equations were used to simulate the adsorption process. The microstructures of newly developed copper removal materials and properties of copper removal are characterized in details by SEM and EDS. Adsorption mechanism of the adsorbent was discussed. The suitable p H value for Cu2+ removal is 5.0 to 6.0 and the adsorption capacity increases with increasing the initial Cu2+ concentration. The adsorption kinetics of the adsorbent could be better described by pseudo second order kinetic model, whereas the adsorption isotherms highly conform to the Freundlich equation. The main crystalline phase of the adsorbent is Fe(Si O3) which can build porous structures conducive to the Cu2+ adsorption.