全氟辛烷磺酸盐(PFOS)在藻渣/小球藻上的吸附行为及机理

为了开发新型廉价生物吸附剂,以高效吸附去除水体中全氟辛烷磺酸盐(PFOS),对小球藻提取生物柴油后的藻渣吸附酸性水体中的PFOS进行了吸附行为及机理的研究。小球藻提取生物质柴油后,比表面积、孔容、孔径几乎没有变化;等电点由3.3降低至2.7;蛋白质含量由51.45%提高到57.35%。在酸性条件下(pH≤3),小球藻和藻渣对PFOS的吸附率均达到99%以上;随着pH值增加至7,二者的吸附去除率迅速降低,但仍保持在22%~26%。小球藻和藻渣对PFOS的最大吸附容量分别为353.69 mg/g和444.83 mg/g。Freundlich模型能较好地拟合二者对PFOS的吸附数据,表明为多层吸附,即小球藻以静电吸引的形式吸附PFOS阴离子,并疏水分配至所含蛋白质中;而藻渣中含量较高的蛋白质对PFOS的疏水性分配作用是导致藻渣吸附量增高的主要原因。     

β-环糊精接枝羧甲基壳聚糖吸附剂的制备及其性能

采用γ-氨丙基三乙氧基硅烷化学修饰活化后的硅胶,以戊二醛为交联剂,接上羧甲基壳聚糖,继而接枝上β-环糊精作为功能单体,制备了一种用于分离富集水样中Cu(Ⅱ)的固相萃取新材料。利用红外光谱(FT-IR)、比表面分析(BET)、X射线衍射光谱(XRD)以及热重分析(TG)等方法对吸附剂进行结构表征。采用火焰原子吸收(FAAS)作为检测手段,考察了溶液p H、振荡时间、吸附剂用量、样品流速、洗脱液浓度和体积等对吸附剂吸附Cu(Ⅱ)的影响。吸附剂饱和吸附容量为9.37 mg/g,最大富集倍数高达350。吸附过程能用准二级动力学模型和Langmuir等温吸附方程进行很好的拟合。应用于环境水样中Cu(Ⅱ)的分离富集与测定,回收率在96.8%~105.2%之间,效果较好。     

PDA的制备及其对水体中邻苯二甲酸二甲酯的去除性能

以二甲基二烯丙基氯化铵(DMDAAC)和丙烯酰胺(AM)为原料,Span-80和Tween-80为乳化剂,液体石蜡为分散相,采用分批加料法,反相乳液聚合制备二甲基二烯丙基氯化铵与丙烯酰胺的共聚物(PDA)。研究内容包括单体配比、引发剂配比、油水体积比和pH值对产物特性粘度的影响。研究获得的优化聚合条件为:单体质量比(DMDAAC∶AM)为2∶8,引发剂质量比(NaHSO3∶K2S2O8)为5∶3,油水体积比为1∶1.2,pH值为8。选用自制PDA用于去除水中邻苯二甲酸二甲酯(DMP)时,在絮凝剂PDA的投加量为0.60 mg/L,pH值为10时,DMP的去除效果最好,去除率达到98.31%。     

纳滤去除饮用水中的PFOS

全氟辛烷磺酸类物质（PFOS）是一种新型持久性有机污染物，对人类健康存在很大威胁，目前世界范围内的水体中均检测到不同浓度的PFOS。研究如何安全有效去除这类新型污染物十分必要。利用HYDRA—COPe10纳滤膜进行PFOS去除研究，在不同操作压力下研究pH、电解质以及与腐殖酸共存对PFOS截留效果的影响。结果表明，随着pH值的增加，截留率上升；二价盐对PFOS截留率的影响要高于一价盐，并且随着二价盐离子强度的增加，截留率上升；腐殖酸共存时截留效率有显著增加，尤其在1mmol／L钙离子存在条件下，PFOS的截留率可达到95．8％，但会引起膜通量下降及膜污染的发生。     

内聚乙醇固定化硫酸盐还原菌同步处理废水中硫酸盐和铬

含Cr(Ⅵ)和硫酸盐废水对生态环境构成严重威胁。以聚乙烯醇和海藻酸钠为交联剂制备一种内聚已醇固定化硫酸盐还原菌(SRB)小球(简称固定化小球),探讨这种新型吸附剂对Cr(Ⅵ)、SO2-4分别为100、200mg/L废水的处理效果。结果表明,固定化小球对废水中Cr(Ⅵ)和SO2-4具有较好去除效果,Cr(Ⅵ)和SO2-4去除量分别高达341.87、1 680μg/g,去除率分别高达97.43%、99.30%。红外谱图、电子扫描图分析表明,固定化小球网状结构构成了细菌免受环境因素干扰的亲水微环境,硫酸盐还原在去除Cr(Ⅵ)和SO2-4过程中发挥了重要作用。     

介孔铁锆复合氧化物的制备及其对Cr(Ⅵ)的吸附性能

以十六烷基三甲基溴化铵(CTAB)为模板剂,以铁(Fe)和锆(Zr)为原料,采用不同Fe/Zr摩尔比例,制备出Fe/Zr复合氧化物吸附剂,对吸附剂的比表面积、孔径分布、晶型结构和零点电位(PH2pc)进行了表征.筛选吸附容量最佳的Fe/Zr吸附剂,考察了吸附条件对其去除水中Cr(Ⅵ)效果的影响,探讨了吸附动力学和等温线规律.结果表明:最佳吸附剂的Fe/Zr摩尔比为5/1,具有典型的介孔材料结构特征;该吸附剂在pH为2～8范围内均有良好的除Cr(Ⅵ)效率;30min内即可达到吸附平衡,最大吸附容量为60.90 mg/g.介孔Fe/Zr复合氧化物与现有除Cr(Ⅵ)吸附剂相比具有更高的吸附能力,是一种具有较好应用潜力的水处理除Cr(Ⅵ)吸附剂.     

分子印迹型TiO_2的制备及其对邻苯二甲酸二(2-乙基)己酯的光催化性能

以邻苯二甲酸二(2-乙基)己酯为模板分子、甲基丙烯酸为功能单体和乙二醇二甲基丙烯酸酯为交联剂,在TiO_2表面合成DEHP分子印迹聚合物,制备了分子印迹型TiO_2(MIP-TiO_2),优化了制备工艺条件。利用傅里叶红外光谱(FIIR)和X-射线衍射(XRD)对MIP-TiO_2进行表征,并考察了MIP-TiO_2对DEHP的光催化降解性能。结果表明,MIP-TiO_2的最佳制备工艺条件为模板分子、单体、交联剂和TiO_2的摩尔比为1∶4∶10∶1.875,反应温度为60℃;聚合时间为18 h。MIPTiO_2仍保持了和TiO_2一样的锐钛矿型结构,对DEHP的光催化效果明显高于TiO_2,对浓度为5 mg·L~(-1)的DEHP的光催化降解效率可达88.15%。     

ZnO改性聚丙烯腈基活性炭吸附水中Cr(Ⅵ)离子的效果

ZnO改性聚丙烯腈制成的活性炭(PAC)是吸附去除水中Cr(Ⅵ)的一种新型吸附剂。从接触时间、吸附剂用量、pH和Cr(Ⅵ)初始浓度等方面对该新型吸附剂吸附性能进行了研究。结果表明,该吸附剂不仅具有良好的吸附效果,而且能够重复使用2次。PAC-0.8(聚丙烯腈置于50 mL、0.8 mol·L~(-1)的Zn(NO3)2水溶液)对Cr(Ⅵ)的吸附效果优于PAC-0.4(聚丙烯腈置于50 mL、0.4 mol·L~(-1)的Zn(NO_3)_2水溶液);PAC-0.8和PAC-0.4对Cr(Ⅵ)的吸附效果优于改性前的聚丙烯腈基活性炭,吸附最适pH范围为2~3,Langmuir等温模型比Freundlich等温模型能更好地描述吸附剂的吸附行为。实验结果可以为ZnO改性聚丙烯腈制成活性炭对废水中Cr(Ⅵ)去除的应用提供科学依据。     

城市污水处理厂二级处理出水中磷深度去除技术

以某城市污水处理厂二级出水为研究对象,分析了其中磷的形态及浓度分布,分别采用FeCl_3、PAC、Al_2(SO_4)_3混凝剂和羟基铁颗粒吸附剂开展了基于化学法和吸附法的深度除磷技术的研究。在相同的水质和环境条件下,对不同形态磷的去除效果进行了分析,并对两者的技术经济性进行了对比。结果表明,该厂二级出水中TP浓度的平均水平为0.332 mg·L~(-1),其中可溶性活性磷酸盐为主要存在形态,占TP浓度的64.16%。与FeCl_3相比,Al_2(SO_4)_3和PAC比较适合本实验原水水质,当其投加量为3 mg·L~(-1)时,出水TP可降至0.05mg·L~(-1)以下。以Al_2(SO_4)_3和PAC作为混凝剂,各种形态的磷均得到不同程度的去除,可溶性活性磷酸盐的去除效果最好,几乎全部得以去除,而颗粒态磷和其他溶解性磷的去除效果较差。通过技术经济比较,Al_2(SO_4)_3在除磷效果和药剂费用上均比PAC占有优势。羟基铁颗粒吸附剂对可溶性活性磷酸盐吸附效果显著,对其他溶解性磷吸附效果较差,当空床接触时间(EBCT)大于10 min时,出水TP可降至0.05 mg·L~(-1)以下。从长期的技术和经济效益综合考虑,吸附剂优于混凝剂。     

NiFe_2O_4/ZnAl-LDH吸附去除水中Cr(Ⅵ)

采用共沉淀法合成磁性复合材料NiFe_2O_4/ZnAl-LDH,通过静态吸附试验考察复合材料去除水中Cr(VI)的性能,系统地研究了溶液初始p H值、吸附剂投加量、吸附时间和温度等因素对Cr(VI)去除效果的影响。结果表明,当溶液初始p H值为2、初始Cr(VI)浓度为50 mg·L-1、吸附剂投加量为4 g·L-1时,吸附过程在240 min内达到平衡,此时Cr(VI)的去除率为89.5%。动力学和吸附等温式的研究表明:NiFe_2O_4/ZnAl-LDH吸附Cr(VI)的过程符合准二级动力学和Langmuir等温吸附模型。热力学参数表明该吸附过程为自发、放热的反应过程,低温有利于吸附剂对Cr(VI)的吸附。吸附剂经4次再生后对Cr(VI)仍有83.1%的去除率,且其在外加磁场的作用下能快速与水溶液分离,因此NiFe_2O_4/ZnAl-LDH可作为去除水中Cr(VI)的良好吸附剂。     

A comparative study on sorption of perfluorooctane sulfonate (PFOS) by chars, ash and carbon nanotubes

Perfluorooctane sulfonate (PFOS), as one of emerging contaminants, has been attracting increasing concerns in recent years. Sorption of PFOS by maize straw- and willow-derived chars (M400 and W400), maize straw-origin ash (MA) as well as three carbon nanotubes (CNTs) was studied in this work. The sorption kinetics of PFOS by the six adsorbents was well fitted by the pseudo-second-order model. CNTs reached equilibrium in 2 h, much faster than those by chars (384 h) and ash (48 h). According to the sorption isotherms, both single-walled carbon nanotubes (SWCNT) and MA had high sorption capacities (over 700 mg g⁻¹), while the two chars had low sorption capacities (below 170 mg g⁻¹) caused by their small BET surface area. In the case of MA, due to its positively charged surface, both hydrophobic interaction and electrostatic attraction involved in the sorption, and the formation of hemi-micelles further favored the sorption. This study suggested that SWCNT and MA were effective adsorbents for PFOS removal from water. Compared to SWCNT, MA is low cost and easy to obtain, so it could be a preferred adsorbent for PFOS removal.     

Adsorption of Co(II) by a carboxylate-functionalized polyacrylamide grafted lignocellulosics

A new adsorbent (PGBS-COOH) having carboxylate functional group at the chain end was synthesized by graft copolymerization of acrylamide onto banana stalk, BS (Musa Paradisiaca) using ferrous ammonium sulphate/H2O2 redox initiator system. The efficiency of the adsorbent in the removal of cobalt [Co(II)] from water was investigated using batch adsorption technique. The adsorbent exhibits very high adsorption potential for Co(II) and under optimum conditions more than 99% removal was achieved. The maximum adsorption capacity was observed at the pH range 6.5-9.0. The equilibrium isotherm data were analysed using three isotherm models, Langmuir, Freundlich and Scatchard, to determine the best fit equation for the sorption of Co(II) on the PGBS-COOH. A comparative study with a commercial cation exchanger, Ceralite IRC-50, having carboxylate functional group showed that PGBS-COOH is 2.8 times more effective compared to Ceralite IRC-50 at 30 degrees C. Synthetic nuclear power plant coolant water samples were also treated by the adsorbent to demonstrate its efficiency in removing Co(II) from water in the presence of other metal ions. Acid regeneration was tried for several cycles to recover the adsorbed metal ions and also to restore the sorbent to its original state.     

Removal of acutely hazardous pharmaceuticals from water using multi-template imprinted polymer adsorbent

Molecularly imprinted polymer adsorbent has been prepared to remove a group of recalcitrant and acutely hazardous (p-type) chemicals from water and wastewaters. The polymer adsorbent exhibited twofold higher adsorption capacity than the commercially used polystyrene divinylbenzene resin (XAD) and powdered activated carbon adsorbents. Higher adsorption capacity of the polymer adsorbent was explained on the basis of high specific surface area formed during molecular imprinting process. Freundlich isotherms drawn showed that the adsorption of p-type chemicals onto polymer adsorbent was kinetically faster than the other reference adsorbents. Matrix effect on adsorption of p-type chemicals was minimal, and also polymer adsorbent was amenable to regeneration by washing with water/methanol (3:1, v/v) solution. The polymer adsorbent was unaltered in its adsorption capacity up to 10 cycles of adsorption and desorption, which will be more desirable in cost reduction of treatment compared with single-time-use activated carbon.     

Selective separation of deltamethrin by molecularly imprinted polymers using a β-cyclodextrin derivative as the functional monomer

A deltamethrin-imprinted polymer (MIP₁) was prepared using bis(-6-O-butanediacid monoester)-β-cyclodextrin (BBA-β-CD) as the functional monomer and toluene 2,4-diisocyanate (TDI) as the cross-linker. In comparison to the molecularly imprinted polymer where β-CD was applied as the functional monomer (MIP₂), MIP₁ showed a higher specific binding capacity (ΔC_P) and an improved imprinting factor (IF) for deltamethrin. The selective recognition experiments demonstrated that compared to MIP₂, MIP₁ could better recognize its template over other substrates that had similar chemical structures. The solid phase extraction (SPE) of deltamethrin using MIP₁ as the adsorbent was further investigated. The recoveries of the molecularly imprinted solid phase extraction (MISPE) column for deltamethrin were 83.2–93.4% with relative standard deviations (RSD) of 2.03–6.19%. The method has been successfully applied to the enrichment of trace deltamethrin from real water samples.     

Analysis and comparison of inertinite-derived adsorbent with conventional adsorbents

To increase U.S. petroleum energy-independence, the University of Texas at Arlington (UT Arlington) has developed a coal liquefaction process that uses a hydrogenated solvent and a proprietary catalyst to convert lignite coal to crude oil. This paper reports on part of the environmental evaluation of the liquefaction process: the evaluation of the solid residual from liquefying the coal, called inertinite, as a potential adsorbent for air and water purification. Inertinite samples derived from Arkansas and Texas lignite coals were used as test samples. In the activated carbon creation process, inertinite samples were heated in a tube furnace (Lindberg, Type 55035, Arlington, UT) at temperatures ranging between 300 and 850 degrees C for time spans of 60, 90, and 120 min, using steam and carbon dioxide as oxidizing gases. Activated inertinite samples were then characterized by ultra-high-purity nitrogen adsorption isotherms at 77 K using a high-speed surface area and pore size analyzer (Quantachrome, Nova 2200e, Kingsville, TX). Surface area and total pore volume were determined using the Brunauer Emmet, and Teller method, for the inertinite samples, as well as for four commercially available activated carbons (gas-phase adsorbents Calgon Fluepac-B and BPL 4 x 6; liquid-phase adsorbents Filtrasorb 200 and Carbsorb 30). In addition, adsorption isotherms were developed for inertinite and the two commercially available gas-phase carbons, using methyl ethyl ketone (MEK) as an example compound. Adsorption capacity was measured gravimetrically with a symmetric vapor sorption analyzer (VTI, Inc., Model SGA-100, Kingsville, TX). Also, liquid-phase adsorption experiments were conducted using methyl orange as an example organic compound. The study showed that using inertinite from coal can be beneficially reused as an adsorbent for air or water pollution control, although its surface area and adsorption capacity are not as high as those for commercially available activated carbons. Implications: The United States currently imports two-thirds of its crude oil, leaving its transportation system especially vulnerable to disruptions in international crude supplies. UT Arlington has developed a liquefaction process that converts coal, abundant in the United States, to crude oil. This work demonstrated that the undissolvable solid coal residual from the liquefaction process, called inertinite, can be converted to an activated carbon adsorbent. Although its surface area and adsorption capacity are not as high as those for commercially available carbons, the inertinite source material would be available at no cost, and its beneficial reuse would avoid the need for disposal.     

Aromatic organic contaminant removal from an aqueous environment by p(4-VP)-based materials

p(4-vinylpyridine) (p(4-VP)) hydrogels were prepared in bulk (macro, 5 × 6 mm) and in nanosizes (370 nm) dimensions. The prepared hydrogels were used to remove organic aromatic contaminates such as 4-nitrophenol (4-NP), 2-nitrophenol (2-NP), phenol (Ph) and nitrobenzene (NB) from an aqueous environment. Important parameters affecting the absorption phenomena, such as the initial concentration of the organic species and the absorbent, absorption rate, absorption capacity, pH and the temperature of the medium, were evaluated for both hydrogel sizes. The absorption capacity of bulk and microgels were found to be 4-NP > 2-NP > Ph > NB. Furthermore, p(4-VP) microgels were embedded in poly(acrylamide) (p(AAm)) bulk hydrogel as a microgel-hydrogel interpenetrating polymer network and proved to be very practical in overcoming the difficulty of using the microgels in real applications. Moreover, it was demonstrated that separately prepared magnetic ferrite particles inserted inside p(4-VP) microgels during synthesis allowed for trouble-free removal of p(4-VP)-magnetic composite microgels from the aqueous environment by an externally applied magnetic field upon completion of their task.     

Phenol removal from wastewater by adsorption on zeolitic composite

It is well known that adsorption is an efficient method of removal of various pollutants from wastewater. The present study examines the phenol removal from water by adsorption on a new material, based on zeolitic volcanic tuff. This compound contains zeolitic tuff and cellulose, another known adsorbent, in a mass ratio of 4 to 1. The performances of the new adsorbent composite were compared with those of a widely used adsorbent material, zeolitic volcanic tuff. The adsorbent properties were tested on batch synthetic solutions containing 1–10 mg L^?1 (1–10 ppm) phenol, at room temperature without pH adjustment. The influence of the adsorbent dose, pH and contact time on the removal degree of phenol from water was investigated. The experimental data were modeled using the Langmuir, Freundlich, and Temkin adsorption isotherms. The Langmuir model was found to best represent our data revealing a monolayer adsorption with a maximum adsorption capacity between 0.12 and 0.53 mg g^?1 at 25 °C, for 2.00 g of adsorbent, depending on the initial phenol concentration. The adsorption kinetic study was performed using a pseudo-first- and pseudo-second-order kinetic models illustrating that phenol adsorption on zeolite composite is well described by pseudo-first kinetic equations. Our results indicated that phenol adsorption on the new adsorbent composite is superior to that on the classic zeolite.     

淀粉-g-丙烯酸/凹凸棒土复合物制备及其吸附废水中NH_4~＋-N性能

采用反相乳液聚合法以凹凸棒土为原料,合成了新型NH4＋-N吸附剂淀粉-g-丙烯酸/凹凸棒土,并进行了氨氮吸附对比实验。结果表明：凹凸棒土氨氮单位吸附量为4.243 mg/g;淀粉-g-丙烯酸/凹凸棒土氨氮单位吸附量为5.301 mg/g,吸附能力比未改性的凹凸棒土提高了25%。淀粉-g-丙烯酸/凹凸棒土的氨氮吸附过程比...     

Comparative study of adsorption of Pb(II) on native garlic peel and mercerized garlic peel

A comparative study using native garlic peel and mercerized garlic peel as adsorbents for the removal of Pb²⁺ has been proposed. Under the optimized pH, contact time, and adsorbent dosage, the adsorption capacity of garlic peel after mercerization was increased 2.1 times and up to 109.05 mg g^?1. The equilibrium sorption data for both garlic peels fitted well with Langmuir adsorption isotherm, and the adsorbent–adsorbate kinetics followed pseudo-second-order model. These both garlic peels were characterized by elemental analysis, Fourier transform infrared spectrometry (FT-IR), and scanning electron microscopy, and the results indicated that mercerized garlic peel offers more little pores acted as adsorption sites than native garlic peel and has lower polymerization and crystalline and more accessible functional hydroxyl groups, which resulted in higher adsorption capacity than native garlic peel. The FT-IR and X-ray photoelectron spectroscopy analyses of both garlic peels before and after loaded with Pb²⁺ further illustrated that lead was adsorbed on the through chelation between Pb²⁺ and O atom existed on the surface of garlic peels. These results described above showed that garlic peel after mercerization can be a more attractive adsorbent due to its faster sorption uptake and higher capacity.     

淀粉-g-丙烯酸/凹凸棒土复合物制备及其吸附废水中NH_4~＋-N性能

采用反相乳液聚合法以凹凸棒土为原料,合成了新型NH4＋-N吸附剂淀粉-g-丙烯酸/凹凸棒土,并进行了氨氮吸附对比实验。结果表明：凹凸棒土氨氮单位吸附量为4.243 mg/g;淀粉-g-丙烯酸/凹凸棒土氨氮单位吸附量为5.301 mg/g,吸附能力比未改性的凹凸棒土提高了25%。淀粉-g-丙烯酸/凹凸棒土的氨氮吸附过程比凹凸棒土更符合Freundlich等温吸附模型。随着pH、温度的升高,凹凸棒土和淀粉-g-丙烯酸/凹凸棒土对NH4＋-N吸附量逐渐增大。