大孔交联甲基丙烯酸缩水甘油酯共聚物的合成及其吸附性能研究(Ⅱ)对磷的吸附性能

前文[1]介绍了大孔交联甲基丙烯酸缩水甘油酯（GMA）与三烯丙基氰尿酸酯（TAC）共聚物（GT）的合成及其孔结构性能。本文研究了GT共聚物经与甘露醇进行功能基化反应制得新型吸磷吸附剂（GTG）。并观察了该吸附剂在诸因素（如pH值、温度及时间等）对磷的吸附性能。实验结果表明：该吸附剂在磷酸盐缓冲液中，pH＝7．0时，温度为37℃，磷的初始含量为10mg／dl时，吸附剂对磷的吸附量可达8．60mg／g吸附剂。     

粉煤灰磁性吸附剂的制备及磷吸附机理

通过化学沉淀法制备了CMS@La_2O_3磁性磷吸附剂。结构及磁性表征显示,氧化镧较均匀的包覆在粉煤灰磁珠表面;样品的比磁化强度达20.35 emu·g~(-1),可实现高效磁分离。利用钼酸铵分光光度法对所得磁性吸附剂的磷吸附性能进行了试验研究。研究表明,其最高磷比饱和吸附量可达19.50 mg·g~(-1),吸附时间、pH值、共存阴离子等因素对磷吸附效果均具有显著影响。吸附动力学拟合表明,CMS@La_2O_3对含磷离子的吸附符合准二级动力学方程,以化学吸附为主,磁性吸附剂对含磷离子的吸附反应过程可由La_2O_3表面羟基化-离子交换模型解释。吸附磷后的CMS@La_2O_3吸附剂经处理后可多次循环使用。     

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。     

大孔交联甲基丙烯酸缩水甘油酯共聚物的合成及其吸附性能研 …

前文介绍了大孔交联甲基丙烯酸缩水甘油酯与三烯丙基氰尿酸酸共聚物的合成及其孔结构性能。本文研究了ＧＴ共聚物经与甘露醇进行功能基化反应制得新型吸磷吸附剂。并观察了该吸附剂在诸因素对磷的吸附性能。     

天然沸石复合吸附剂处理含磷废水的研究

本文研究了天然沸石复合吸附剂的制备及用此吸附剂对含磷废水的吸附处理。结果表明:吸附剂的吸附容量大于22mg/g,磷的去除率在98％以上。     

三种新型吸附剂的合成,改性及性能研究

本文介绍了三类新型吸附剂的合成与改性，测定了孔结构参数和吸附性能。结果表明：这些吸附剂对胆固醇均有吸附，最高吸附率可达６０．８％，而对高密度脂蛋白则不吸附。     

稀土吸附剂城市污水深度除磷

采用以分子筛为载体、负载镧制成复合吸附剂对城市污水进行深度除磷.实验结果表明:研制的稀土吸附剂适于处理弱酸性废水.对于城市污水含磷浓度为1.0 mg·L-1,当pH值3～7,吸附剂的投加量在0.06 g·L-1,吸附3 h时,磷的去除率可达99.5%,出水pH值在6.0～8.5之间.     

Characteristic and Mechanism of Cr（VI） Biosorption by Buckwheat Hull from Aqueous Solutions

农业废弃物荞麦皮作为生物吸附剂去除水中Cr（VI）,研究了荞麦皮对Cr（VI）的去除动力学以及溶液pH、吸附剂用量和Cr（VI）初始浓度对去除效率的影响;通过FT-IR,XPS,SEM．EDX对荞麦皮表面组成和结构进行表征,探索荞麦皮去除Cr（VI）的机理．结果显示：荞麦皮对Cr（VI）有很高的去除效率．常温下5．0g·L^-1的荞麦皮在pH=2.0下对100mg·L^-1Cr（V0溶液的去除率可达99．87％．荞麦皮对Cr（VI）的去除率随溶液pH降低而升高,在pH=2.0时达到最大;随吸附剂用量增加而增大;随Cr（VI）初始浓度增加而减小．单位质量荞麦皮对Cr（V1）的去除量随吸附剂用量增加而减小;随Cr（VI）初始浓度增加而增加,最后趋于稳定．在20℃,pH=2．0,吸附用量为5．0g·L^-1时,荞麦皮对Cr（W）的最大去除容量约为36．4mg·g^-1．荞麦皮吸附去除Cr（Vb的过程符合准二级吸附动力学．FT-IR,XPS和SEM-EDX分析结果表明：荞麦皮是一个多孔材料,表面存在羧基、氨基、羟基等活性基团;荞麦皮对Cr（VI）的去除是一个吸附一还原耦合的过程,包括Cr（VI）在荞麦皮表面上的静电吸附,以及此后的固相还原和对还原态的Cr（Ⅲ）再吸附;Cr（Ⅲ）的吸附主要是通过与荞麦皮表面的羧基、氨基的配位,以及与其中的阳离子发生离子交换作用实现的．     

原位合成羟基磷灰石/壳聚糖复合吸附剂及除氟特性研究

利用原位共沉淀法合成了羟基磷灰石/壳聚糖复合吸附剂,通过扫描电镜、X射线粉末衍射、红外光谱和N2吸附-脱附曲线,研究复合前后羟基磷灰石的理化特征变化。实验结果表明与壳聚糖复合后羟基磷灰石的晶型并没有改变,只是结晶度有所降低,且复合后表面形成了不规则的凹凸结构,表面粗糙度增加。比表面积从106.75m2/g增加到127.58m2/g。复合吸附剂孔径大部分集中在10~50nm,属于介孔结构。利用Langmuir和Freundlich吸附等温方程对实验数据进行了拟合,对比相关系数R2值,Langmuir模型能更好地描述该吸附过程。复合吸附剂对氟离子的吸附符合拟二级反应动力学方程。计算了吸附热力学和动力学参数值,探讨了复合吸附剂对氟离子的吸附机理。ΔG0<0、ΔH0>0和ΔS0>0,说明复合吸附剂对氟离子的吸附是自发的、吸热的熵增过程,温度升高有利于吸附。吸附活化能(Ea)=15.03kJ·mol-1,迁移能(E)=7.639kJ·mol-1,说明该吸附过程以物理吸附为主。     

大孔吸附树脂提取麦拓莱霉素的工艺研究

研究了用大孔吸附树脂从发酵液中分离提取新型大环内酯类抗生素-麦拓莱霉素的吸附工艺过程，对吸附条件进行了优化，得到了适宜的操作条件．结果表明：NKA树脂为最佳吸附剂：吸附最佳pH值为10．32；吸附流速选择为1ml／min；NaCl的加入对吸附不利，选择NaCl浓度为0．6％左右，本实验条件下，发酵液中的麦拓莱霉素浓度为0．18mg／ml；NKA的吸附量可达33．7mg／g树脂。     

南四湖各生态功能湖区垂向沉积物的磷吸附特征

研究了南四湖各生态功能湖区(养殖区、禁渔区、航道及湖滨带)垂向不同深度沉积物对磷的吸附动力学及等温吸附曲线,并分析了沉积物各形态磷与磷吸附特征参数的相关关系.研究结果表明:①各层沉积物对磷的吸附在10h内基本达到平衡,最大吸附量Qmax随着沉积深度的增加而增大;②随着沉积深度的增加,吸附-解吸平衡浓度Cepc和本底吸附态磷ωNAP含量均逐渐减小,吸附效率m逐渐增大;③吸附-解吸平衡浓度Cepc与Ex-P、Fe-P含量显著正相关,最大吸附量Qmax与Ex-P、org-P和TP含量均呈显著负相关关系,本底吸附态磷ωNAP与Ex-P、De-P含量呈显著正相关关系,吸附效率m仅与org-P含量呈显著正相关关系.     

氨基功能化纳米复合材料对磷酸盐的吸附研究

合成了4种氨基(乙二胺(EDA), 二乙烯三胺(DETA), 三乙烯四胺(TETA)和四乙烯五胺(TEPA))功能化纳米复合材料(NH₂-NCMs, 分别命名为EDA-NCMs, DETA-NCMs, TETA-NCMs和TEPA-NCMs). 采用FTIR(傅立叶变换红外光谱分析), TG/DTG(热重差热分析), XPS(X-射线光电子能谱分析)等手段对其进行了表征, 并考察了其对水中磷酸盐的吸附性能. 结果表明: 溶液pH对其吸附性能影响较大, 在pH为2.5的条件下, 4种吸附剂对磷酸盐的吸附效果最佳; 在5 min内即可达到平衡吸附量的90%; 4种吸附剂对磷酸盐的吸附均符合Langmuir等温吸附模型; 吸附行为均符合准二级速率模型; 吸附反应为自发进行的放热反应和熵减的过程; 推测其吸附机理以静电作用力为主. 4种吸附剂用于磷酸盐含量为50 mg/L的废水处理的吸附率均大于97%, 均达到一级A出水的排放标准(≤1.53 mg/L, 以PO₄^3-计).     

弱碱性阴离子交换树脂分离1,6—二磷酸果糖的研究

采用弱碱性阴离子交换树脂HJ-30对发酵液中1，6-二磷酸果糖的分离进行了研究。详细地研究了树脂的吸附和脱附性能。实验结果表明，HJ-30树脂对FDP的吸附量达0．28gFDP／g湿树脂，以0．05mol／LNaCl洗脱光机磷和1mol／LNaCl洗脱1，6-二磷酸果糖，产品的收率和纯度分别为92％和99．4％。     

锆、铁水合氧化物对磷酸根的吸附

将氯氧化锆、三氯化铁分别与双氧水和氨水反应,生成锆、铁水合金属氧化物。用这两种氧化物作为吸附剂对水中的磷进行吸附。讨论了吸附过程对吸附容量的影响因素(温度、pH、时间)及除磷机理。实验结果表明,在低的pH值下,吸附容量最大;该吸附过程主要是以离子交换反应进行的吸热过程;可以用Freundlich方程表示静态吸附的吸附等温线;吸附动力学符合一级反应方程。     

盾构渣土基碳复合陶粒的制备及除磷性能

以固体废弃物地铁盾构渣土、稻草秸秆和氧化镁为主要原料,通过烧结法制备了一种盾构渣土基碳复合陶粒。考察了陶粒吸附磷的主要影响因素及平衡吸附量,并采用模型对实验数据进行拟合分析。结果表明,当盾构渣土、稻草秸秆粉末和氧化镁质量比为7∶2∶1,在最佳烧结条件700℃烧结可得到除磷性能最佳的陶粒。当吸附pH=6.3时,陶粒具有较高的磷吸附性能。吸附在12 h内基本能达到吸附平衡,该过程适合准二级动力学方程。盾构渣土基碳复合陶粒对磷酸盐的吸附符合Temkin等温模型,随温度升高吸附量逐渐增大,40℃下最大吸附量为12.76 mg/g。热力学参数ΔH=5.64 k J/mol0,ΔS=8.00 J/(K·mol)0,ΔG=3.16 k J/mol0,呈吸热、非自发的热力学特征,陶粒吸附磷后可通过2.0 mol/L的氢氧化钠溶液重新解吸回收。     

Distinguishing Adsorption and Surface Precipitation of Phosphate on Goethite (alpha-FeOOH)

The reaction between phosphate and goethite changes from adsorption into surface precipitation with no discernible changes in the adsorption isotherm. Distinguishing the two processes, by plotting the loss of phosphate from solution versus final phosphate concentration or based on theoretical calculations, is difficult. This paper presents a method for distinguishing between the two processes based on the change in zeta potential with increasing adsorption. During adsorption, the incoming phosphate results in a more negative surface charge as the more acidic phosphate ion replaces a less acidic surface hydroxyl. The amount of negative charge imparted to the surface should vary linearly with surface coverage for adsorption. Phosphate that is bound to a surface precipitate, on the other hand, imparts a much smaller negative charge to the surface, since there is no change in the character of the surface due to the additional phosphate. Zeta potential measurements of phosphated goethite at varying solution pH values and surface coverages are used to determine the transition point from adsorption to surface precipitation. The transition occurs at dissolved phosphate concentrations much lower than those calculated for phosphate in equilibrium with goethite and iron phosphate. Copyright 2000 Academic Press.     

Removal of phosphate by aluminum oxide hydroxide

The development and manufacture of an adsorbent to remove phosphate ion for the prevention of eutrophication in lakes are very important. The characteristics of phosphate adsorption onto aluminum oxide hydroxide were investigated to estimate the adsorption isotherms, the rate of adsorption, and the selectivity of adsorption. Phosphate was easily adsorbed onto aluminum oxide hydroxide, because of the hydroxyl groups. The adsorption of phosphate onto aluminum oxide hydroxide was influenced by pH in solution: the amount adsorbed was greatest at pH 4, ranging with pH from 2 to 9. The optimum pH for phosphate removal by aluminum oxide hydroxide is 4. The selectivity of phosphate adsorption onto aluminum oxide hydroxide was evaluated based on the amount of phosphate ion adsorbed onto aluminum oxide hydroxide from several anion complex solutions. It is phosphate that aluminum oxide hydroxide can selectively adsorb. The selectivity of phosphate onto aluminum oxide hydroxide was about 7000 times that of chloride. This result indicated that the hydroxyl groups on aluminum oxide hydroxide have selective adsorptivity for phosphate and could be used for the removal of phosphate from seawater.     

Some peculiarities in the specific adsorption of phosphate ions on hematite and gamma-Al2O3 as reflected by radiotracer studies

The specific adsorption of radiolabeled phosphate ions from perchlorate supporting electrolyte onto gamma-Al2O3 and hematite powder has been investigated. The pH dependence of the adsorption of phosphate species was compared with that of sulfate ions. It was demonstrated that in contrast to the behavior of sulfate ions the pH dependence of phosphate ions goes through a maximum. On the other hand, it was found that the reversible adsorption of phosphate ions is accompanied by the formation of strongly chemisorbed species. Results obtained from a study of the competitive adsorption of sulfate and phosphate ions at various pH values are reported and interpreted. An attempt is made to correlate the experimental findings with the models for anion adsorption reported in the literature.     

Kinetic modeling of liquid-phase adsorption of phosphate on dolomite

The adsorption of phosphate from aqueous solution on dolomite was investigated at 20 and 40 degrees C in terms of pseudo-second-order mechanism for chemical adsorption as well as an intraparticle diffusion mechanism process. Adsorption was changed with increased contact time, initial phosphate concentration, temperature, solution pH. A pseudo-second-order model and intraparticle diffusion model have been developed to predict the rate constants of adsorption and equilibrium capacities.The activation energy of adsorption can be evaluated using the pseudo-second-order rate constants. The adsorption of phosphate onto dolomite are an exothermically activated process. A relatively low activation energy and a model highly fitting to intraparticle diffusion suggest that the adsorption of phosphate by dolomite may involve not only physical but also chemisorption. This was likely due to its combined control of chemisorption and intraparticle diffusion. However, for phosphate/dolomite system chemical reaction is important and significant in the rate-controlling step, and for the adsorption of phosphate onto dolomite the pseudo-second-order chemical reaction kinetics provides the best correlation of the experimental data.     

改性高粱秸秆对磷酸根的吸附性能研究

将改性高粱秸秆用于磷酸根的吸附,研究了时间、酸度、温度以及改性高粱秸秆用量等因素对其吸附性能的影响。结果表明,在常温下,改性高粱秸秆对磷酸根具有良好的吸附性能,吸附时间快。改性高粱秸秆对磷酸根的吸附符合Langmuir和Freundli-ch吸附等温方程及准二级动力学方程,吸附过程以单分子层物理吸附为主。