不同分子质量的腐殖酸对溴离子在MIEX树脂上吸附行为的影响

采用静态吸附法研究了不同分子量的腐殖酸对溴离子(Br?)在MIEX树脂上吸附行为的影响. 结果表明,pH为中性时,4种腐殖酸(分子量分别为小于1000, 1000?5000, 5000?10000, 大于10000)使MIEX树脂对Br?的去除率从80.05%分别降至75.39%, 26.32%, 42.67%和49.03%,而酸性(pH<5.0)或碱性(pH>9.0)时,各种腐殖酸则会促进Br?去除,pH为11.0时去除效率增加最明显. 分子量大于10000的腐殖酸可将吸附平衡时间由60 min缩短至20 min,分子质量1000?5000和5000?10000的腐殖酸可将吸附平衡时间缩短至40 min. 但不论有无腐殖酸,MIEX树脂对Br?的吸附过程均符合拟二级反应动力学模型. 不同分子量的腐殖酸均能明显降低Br?在MIEX树脂上的吸附平衡容量,分子量大于10000的腐殖酸影响最大,但均不改变吸附平衡模型类型,吸附平衡规律用Langmuir与Freundlich模型均可很好描述. 不同分子量的腐殖酸对MIEX树脂去除Br?的影响与溶液pH值密切相关,腐殖酸会加速Br?在树脂上的吸附过程,但不改变吸附平衡及动力学模型类型.     

基于响应曲面法的磁性离子交换树脂去除甲基橙和刚果红的优化

选取树脂用量、溶液初始pH值、吸附质浓度和吸附时间四个因素,用Box-Behnken响应曲面法分别建立了甲基橙和刚果红在磁性离子交换(MIEX)树脂上吸附的二次多项式回归模型,使用方差及显著性分析证明了回归方程的可靠性。优化了MIEX树脂去除甲基橙和刚果红的工艺参数,探究了最佳工艺条件下MIEX树脂对甲基橙(刚果红)的去除效果。使用NaCl再生饱和吸附后的MIEX树脂,用扫描电镜对吸附前后的树脂进行表征。结果表明,在最优工艺条件下,MIEX树脂对甲基橙和刚果红的去除率最高可达99.12%和98.29%。溶液初始pH值和树脂用量之间的交互作用对MIEX树脂去除甲基橙和刚果红有显著影响。NaCl溶液对MIEX树脂的再生效果显著。     

MIEX对水中DBP的去除效果及机理分析

邻苯二甲酸二丁酯(DBP)是水源水中常见的内分泌干扰物。以新型的饮用水处理材料离子交换树脂(MIEX)为吸附剂,以DBP为目标污染物,从动力学、吸附等温线、电荷密度测定、红外光谱表征、X射线光电子能谱以及共存组分影响等方面分析了MIEX去除DBP的效果和机理。MIEX去除DBP的过程仅需20 min即达到平衡,可用准二级动力学描述,中性溶液中DBP的饱和吸附量为0.944 mg·g-1。中性条件下DBP带电量仅为2.7×10~(-3)mmol·mmol~(-1),MIEX与DBP间的作用并非离子交换,而是以DBP分子与MIEX基材间的疏水作用以及氢键作用为主。高浓度SO_4~(2-)和Cl~-不会对DBP的去除效果产生影响;高浓度的腐殖酸(HA)轻微抑制DBP的去除,但微量DBP并不会影响MIEX对HA的去除效果。因此,MIEX作为能高效去除水中天然有机物的新型材料,也可用于去除其中微量的DBP,适用于饮用水复合污染的处理。     

MIEX对水中DBP的去除效果及机理分析

邻苯二甲酸二丁酯(DBP)是水源水中常见的内分泌干扰物。以新型的饮用水处理材料离子交换树脂(MIEX)为吸附剂,以DBP为目标污染物,从动力学、吸附等温线、电荷密度测定、红外光谱表征、X射线光电子能谱以及共存组分影响等方面分析了MIEX去除DBP的效果和机理。MIEX去除DBP的过程仅需20 min即达到平衡,可用准二级动力学描述,中性溶液中DBP的饱和吸附量为0.944 mg·g^-1。中性条件下DBP带电量仅为2.7×10^-3 mmol·mmol^-1,MIEX与DBP间的作用并非离子交换,而是以DBP分子与MIEX基材间的疏水作用以及氢键作用为主。高浓度 和 不会对DBP的去除效果产生影响;高浓度的腐殖酸(HA)轻微抑制DBP的去除,但微量DBP并不会影响MIEX对HA的去除效果。因此,MIEX作为能高效去除水中天然有机物的新型材料,也可用于去除其中微量的DBP,适用于饮用水复合污染的处理。     

MIEX树脂去除水源中突发性六价铬污染的参数优化

水源水中加入六价铬模拟水源突发性六价铬污染,采用单因素和响应曲面法建立了二次多项式回归模型,研究了磁性离子交换(MIEX)树脂去除水源突发性六价铬污染的可行性,对工艺参数进行了优化.结果表明,MIEX树脂可快速去除六价铬,约40 min时达吸附平衡;六价铬去除率随树脂用量增加而增加,随铬浓度增加而降低,pH为4时达最大值;回归模型可有效预测六价铬在MIEX树脂上的吸附.树脂用量与六价铬初始浓度、树脂用量与溶液pH、六价铬初始浓度与溶液pH间的交互作用对六价铬的去除有显著影响.最优参数下MIEX树脂对六价铬的去除率为99.99%.     

磺胺嘧啶在颗粒活性炭和碳纳米管上的吸附特性

近年来,水环境中抗生素的去除成为关注热点。研究讨论了磺胺嘧啶在颗粒活性炭(GAC)和多壁碳纳米管(MWCNT)上的吸附特性,并考察了pH、离子强度和腐殖酸等因素对吸附的影响。结果表明,pH对吸附效果有着显著的影响;腐殖酸的存在与磺胺嘧啶形成了竞争吸附;离子强度的变化对吸附效果没有很大影响。     

不溶性腐殖酸吸附Cr(Ⅵ)的研究

研究了不溶性腐殖酸对六价铬的吸附作用。进行了反应接触时间、pH值、IHA投加量、光照条件、温度等对反应的影响研究,确定了最佳反应条件,同时应用未处理的腐殖酸进行对比研究,说明不溶性腐殖酸的作用效果。试验表明在反应接触时间60 min、pH值为7左右、不溶性腐殖酸投加量为5 g/L和Cr(Ⅵ)的质量浓度为5.36 mg/L的条件下,不溶性腐殖酸对铬离子去除可达95%,比未处理的腐殖酸对铬离子去除提高近1倍。并绘制了不溶性腐殖酸对铬离子的反应动力学曲线和吸附等温线。     

腐殖酸对铜的吸附与解吸特征

采用铜离子选择电极研究了铜在腐殖酸两组分(富里酸FA、胡敏酸HA)中的吸附-解吸特征,以及介质pH值对这种吸附-解吸的影响。试     

高锰酸钾与液氯联用控制水库水源三卤甲烷生成

以东北某水库受污染水源为研究对象,利用3种树脂(XAD-7、AG-MP-50、WA-10)将水中的溶解性有机物(DOM)分为疏水酸性物质(HPOA)、疏水碱性物质(HPOB)、疏水中性物质(HPON)、亲水酸性物质(HPLA),亲水碱性物质(HPIB)及亲水中性物质(HPIN),考察了采用高锰酸钾与液氯联用技术去除DOM及三卤甲烷(THMs)的效果.试验结果表明,原水DOM中疏水性物质是三卤甲烷的主要前体物;高锰酸钾与液氟联用预氧化工艺的THMs生成量较单独预氯化降低了55.19%,6种DOM组分的三卤甲烷生成势(THMFP)明显减少;高锰酸钾与氯联用可有效去除THMFP,降低饮用水中THMs的生成.     

溴离子对水体中DOM亲水性有机组分氯化消毒过程中三卤甲烷生成的影响

采用树脂分离技术对水体中的溶解性有机物(DOM)进行分离富集,得到疏水性中性物(HPON)、疏水性碱(HPOB)、疏水性酸(HPOA)、亲水性中性物(HPIN)、亲水性碱(HPIB)和亲水性酸(HPIA)等6种组分,以其中HPIN、HPIB、HPIA作为研究对象,考察了在高浓度溴离子的影响下,亲水性有机物形成三卤甲烷(THMs)的变化情况。结果表明,溴离子的加入,HPIN是加氯消毒时产生三卤甲烷(THMs)的主要前提物质,且形成THMs的活性HPIN≥HPIA>HPIB,而且三种亲水性有机物对THMs贡献因子n明显增加,同时大大增加了亲水性组分在氯消毒后的总致癌风险。     

Adsorption of Lead and Cadmium on Ca-Deficient Hydroxyapatite

A Ca-deficient hydroxyapatite(d-HAp) has been used to remove lead and cadmium from their mixed ions solution. The effect of pH, coexistent calcium and magnesium ions, and humic acid on the adsorption efficiency were investigated. The results showed that this d-HAp adsorbed both Cd²⁺ and Pb²⁺ efficiently within a wide pH range. The existence of humic acid reduced the removal efficiency of Cd²⁺ and Pb²⁺. The addition of Ca²⁺ and Mg²⁺ with a concentration of 500 mg/L only slightly reduced the removal efficiency. The adsorption kinetics was described by pseudo-second-order reaction model and the adsorption isotherm followed the Langmuir model.     

Application of combined coagulation-ultrafiltration membrane process for water treatment

The objectives of this research are to identify the membrane fouling potential due to different fractions of NOM and correlate the physicochemical properties of NOM and membranes with the adsorption of humic substances on membrane and investigate the mechanism of coagulation affecting UF, and find the optimum conditions of the combined of coagulation with UF membrane filtration for NOM removal. For Nakdong river water, the humic acid fraction was the most reactive precursor fraction for the formation of the ratio of THMFP/DOC (STHMFP) and TOXFP/DOC (STOXFP). The result of adsorption kinetics tests showed that hydrophobic organics adsorbed much more quickly than hydrophilic organics on both membranes. Thus, hydrophobic compounds exhibited a preferential adsorption onto membrane. In case of the effect of membrane properties on the adsorption of organic fractions, the adsorption ratio (C₁/C_e) was greater for the hydrophobic membrane than for the hydrophilic membrane regardless of the kind of organic fractions. For combined coagulation with membrane process, flux reduction rate showed lower than the UF process alone. Also, the rate of flux decline for the hydrophobic membrane was considerably greater than for the hydrophilic membrane. Applying the coagulation process before membrane filtration showed not only reduced membrane fouling, but also improved removal of dissolved organic materials that might otherwise not be removed by the membrane. That is, during the mixing period, substantial changes in particle size distribution occurred under rapid and slow mixing conditions due to the simultaneous formation of microflocs and NOM precipitates. Therefore, combined pretreatment using coagulation (both rapid mixing and slow mixing) improved not only dissolved organic removal efficiency but also DBP (Disinfection By-Product) precursor's removal efficiency.     

腐植酸对阿特拉津的吸附特性研究

采用批量平衡震荡法研究了腐植酸对不同浓度阿特拉津的吸附量随时间变化的规律,并利用傅里叶红外光谱(FTIR)和电子顺磁共振波谱(ESR)2种方法探讨其吸附机理.结果表明,腐植酸对阿特拉津的吸附量与吸附时间符合对数和双曲线函数关系,吸附初始阶段是一个快速过程,随着时间的增加,吸附速率逐渐减慢,最后趋于平衡.阿特拉津初始浓度...     

腐殖酸树脂处理含Zn^2＋、Ni^2＋废水的研究

利用泥炭为原料制备出腐殖酸树脂,在动态条件下,研究了腐殖酸树脂对重金属离子Zn^2＋、Ni^2＋的吸附效果及吸附条件。结果表明,在20℃,流速为4mL／min,pH值为5．0～7．0,含Zn^2＋、Ni^2＋浓度分别为70mg／L的废水经过腐殖酸树脂处理,Zn“、Ni。’去除率可达98％以上,且处理后的废水pH值近中性。含Zn^2＋、Ni^2＋浓度分别为32．5mg／L和29．4mg／L,pH值为5．9的电镀废水经腐殖酸树脂处理后,废水中Zn^2＋、Ni^2＋含量明显低于国家排放标准。     

腐植酸树脂处理含重金属离子废水可行性探讨

利用泥炭为原料制备腐植酸树脂。在动态条件下,研究了腐植酸树脂对重金属离子Zn2+、Ni2+的吸附效果及吸附条件并探讨了吸附与解吸再生机理:主要吸附形式为离子交换吸附和络合吸附。实验结果表明,在20℃,流速为4mL/min,pH值为5.0～7.0条件下,含Zn2+、Ni2+质量浓度均为70mg/L的废水,经腐植酸树脂处理后,Zn2+、Ni2+去除率可达98%以上,且处理后废水近中性。含Zn2+、Ni2+质量浓度分别为32.5mg/L和29.4mg/L,pH值为5.9的电镀废水,经腐植酸树脂处理后,废水中Zn2+、Ni2+含量显著低于国家排放标准允许值。     

Adsorption of humic acid onto pillared bentonite

Pillared bentonite, a clean and cost-effective adsorbent with high specific areas of 111.3 m²/g and high basalspacing of 1.98 nm, was prepared for the removal of humic acid from water. It is effective for the removal of humic acid with a high adsorption capacity of 537 mg/g, and adsorption is favored under acid conditions. Adsorption is dependent on ionic strength and dissolved NaCl enhanced adsorption. Over 97% removal was observed under natural pH conditions from humic acid solutions containing 10 mg/L Ca²⁺ or Mg²⁺, which suggests that pillared bentonite can be an effective adsorbent for the removal of humic acid for drinking water purification. Pillared bentonite can be regenerated with NaOH, and the regeneration efficiency reaches 83% and 85% when the concentration of NaOH reaches 0.025 and 0.05 mol/L. The mechanism for adsorption of humic acid to pillared bentonite is discussed.     

Humic acid-immobilized polymer/bentonite composite as an adsorbent for the removal of copper(II) ions from aqueous solutions and electroplating industry wastewater

In this study, humic acid (HA) was immobilized onto amine-modified polyacrylamide/bentonite composite (Am-PAA-B) which was prepared by direct intercalation polymerization technique and the product (HA-Am-PAA-B) was used as an adsorbent for the removal of copper(II) ions from aqueous solutions. The surface characteristics of bentonite, Am-PAA-B and HA-Am-PAA-B were investigated. The adsorbent behaved like a cation exchanger and more than 99.0% Cu(II) ions’ removal was observed at the pH range 5.0–6.0. Kinetic and isotherm experiments showed that amount of Cu(II) ions adsorbed increases with increase of the initial concentration and temperature. The adsorption kinetic data were interpreted by pseudo-first-order and pseudo-second-order rate equations. The suitability of Langmuir, Freundlich and Dubinin–Radushkevich (D-R) adsorption models to the equilibrium data was investigated. The Langmuir isotherm was found to provide the best theoretical correlation of the experimental equilibrium data. The thermodynamic and kinetic activation parameters were derived to predict the nature of adsorption process and discussed in detail. The isosteric heat of adsorption was constant even after increase in surface loading. The removal efficiency of HA-Am-PAA-B was tested using electroplating industry wastewater. The desorption of adsorbed Cu(II) ions was achieved by 0.1 M HCl and four adsorption/desorption cycles were performed without significant decrease in the adsorption capacity.     

Adsorption of Congo Red Dye over Pendent Chlorobenzylidine Rings Present on Polythioamide Resin: Kinetic and Equilibrium Studies

The removal of Congo Red (CR) from an aqueous solution, using aromatic polythioamide resin (PTA) was studied. The effective pH and equilibrium time for the maximum adsorption of the CR on the PTA is found to be 7 and 45 min, respectively. Among the three kinetic models studied, the pseudo-second order kinetic model describes adsorption of the CR on the PTA efficiently. The maximum adsorption capacity of PTA for CR calculated from the Langmuir isotherm is 452.1 mg/g. The surface morphology of the PTA and dye adsorbed PTA were determined using scanning electron microscopy. The adsorption efficiency of the PTA was retained even after four cycles.