Functionally Modified Cellulose Nanocrystals as an Adsorbent for Anionic Dyes

Cellulose nanocrystal was modified with poly(N,N-diethylaminomethyl methacrylate) to prepare an adsorbent containing amine groups for removing anionic dyes from waste water. The prepared adsorbent was characterized by Fourier-transform infrared spectrometry(FT-IR), X-ray photoelectron spectroscopy(XPS), and thermogravimetric analysis(TGA). The adsorption was affected by various factors, such as the contact time, adsorbent dosage, dye solution pH value, initial dye concentration, and ionic strength. The results revealed that amine functional groups mainly contribute to the adsorption of azo dyes(AO7). The adsorbent showed pseudo-secondorder adsorption kinetics, indicating that the dye molecules were chemisorbed on the adsorbent. The adsorption isotherm was found to fit better with the Langmuir isotherm model than with the Freundlich isotherm model.

Synthesis of Three-Dimensional Hierarchical Flower-Like Mg–Al Layered Double Hydroxides with Excellent Adsorption Performance for Organic Anionic Dyes

In this work,a facile and effective strategy to prepare three-dimensional(3D)hierarchical flower-like Mg–Al layered double hydroxides(3D-LDH)was developed via a one-step double-drop coprecipitation method usingγ-Al 2O 3particles as a template.The characterization and experimental results showed that the calcined product,3D-LDO,features a large specific surface area of 204.2 m^(2)/g,abundant active sites,and excellent adsorption performance for Congo red(CR),methyl orange(MO),and methyl blue(MB).The maximum adsorption capacities of 3D-LDO for CR,MO,and MB were 1428.6,476.2,and 1666.7 mg/g,respectively;such performance is superior to that of most reported adsorbents.The adsorption mechanism of organic anionic dyes by 3D-LDO was extensively investigated and attributed to surface adsorption,the memory effect of 3D-LDO,and the unique 3D hierarchical flower-like structure of the adsorbent.Recycling performance tests revealed that3D-LDO has satisfactory reusability for the three organic anionic dyes.

Preparation of a Novel Acid Doped Polyaniline Adsorbent for Removal of Anionic Pollutant from Wastewater

Polyaniline(PANI) was one of the most extensively studied adsorbents due to its low cost and good environmental stability. The objective of the current study was to improve the selective capabilities of PANI for anionic dyes. We found that the acid doped PANI prepared with hydrochloric acid and p-toluenesulfonic acid(PTSA) could selectively adsorb anionic dyes. It exhibited very good selectivity for OG dye, the mechanism was proposed based on the chemical interaction of PANI with the sulfonate group of the dyes. The effects of solution p H, initial dye concentration, and different HCl/PTSA mole ratios on the adsorption capacity of OG have been investigated. Kinetic simulations indicated that the adsorption process could be well represented by pseudo-second-order kinetic plots. The isothermal adsorption curve fitting also showed that the adsorption process could be well described by the Langmuir isothermal equation. The results showed that acid doped PANI could be employed as a promising adsorbent for anion removal from dye wastewater.

Efficient Removal of Reactive Orange 107 Dye from Aqueous Media by Shrimp Shell Derived Chitosan Functionalized Magnetic Nanoparticles

In present work chitosan functionalized magnetic nanoparticles (CMNPs) were successfully prepared and investigated for the removal of Reactive Orange 107 dye (RO 107) from water. The chitosan was extracted from shrimp shells (Penaeus merguiensis) and was characterized by solubility test and fourier transform infrared spectroscopy (FTIR). Degree of deacetylation of chitosan was examined by 1H-NMR and potentiometric titration method. Thereafter, the chitosan was used for synthesis of CMNPs. The synthesized CMNPs were characterized by FTIR, scanning electron microscopy-energy dispersive spectroscopy (SEM-EDS), thermal gravimetric analysis (TGA) and atomic force microscopy (AFM). Effects of various variables such as contact time, pH, stirring speed, adsorbent dosage, temperature, and concentration of electrolyte on extraction efficiency were evaluated. Freundlich isotherm model fits better that shows the removal of RO 107 with CMNPs by multilayer adsorption behaviour. Furthermore, kinetic study showed that adsorption process followed pseudo-second order kinetic model regulated by chemisorption. Thermodynamic analysis explained that adsorption of RO 107 onto CMNPs was endothermic as well as spontaneous. The developed CNMPs were applied to environmental remediation of spiked RO 107 treated waste water samples with 96.20% removal potential, hence, offered an effective sorbent for removal of RO 107 contaminated water samples.

沸石咪唑酯骨架-8的制备及其对刚果红的吸附性能

为制备印染废水的吸附材料,以六水合硝酸锌和2-甲基咪唑为原材料,以去离子水作溶剂,采用水溶剂法制备沸石咪唑酯骨架-8(ZIF-8)材料。借助扫描电子显微镜、红外光谱仪、X射线衍射仪等探究ZIF-8材料的结构,测试其对阴离子刚果红染料的吸附性能,并分析其吸附机制。结果表明:ZIF-8颗粒大小均匀,表面光滑,呈多面体结构;其热裂解温度为258℃,具有良好的热稳定性;ZIF-8对刚果红的吸附更符合准二级动力学模型和Langmuir吸附等温线模型,即以化学吸附为主且吸附位点等效;吸附过程为自发进行的放热反应,低温有利于吸附;在温度为20℃、pH值为7的条件下,ZIF-8对95 mg/L的刚果红溶液的吸附效果最佳,吸附量可达671.41 mg/g。

双氰胺甲醛改性汉麻纤维吸附剂的制备及对阴离子染料的吸附

针对双氰胺甲醛(DDF)对染料废水脱色时pH适用范围狭窄、难分离回收等问题,采用3-氨丙基三乙氧基硅烷(APTES)偶联剂将DDF接枝到汉麻纤维(HF)上,制备一种适用于去除阴离子染料的广域pH高效吸附剂(HF-APT-DDF)。考察了不同因素对单一组分和混合组分下刚果红(CR)、酸性兰9(AO 9)和活性嫩黄K-6G(RBY K-6G)3种染料吸附性能的影响。结果表明:HF-APT-DDF在pH=4~10的范围内均具有良好的脱色效果;在温度为298 K、染料初始浓度为20 mg/L、pH为8、吸附时间为1.5 h、投加量为1.0和1.4 g/L时,HF-APT-DDF对单一组分和混合组分染料的脱色率均超过97%,对CR、AO 9和RBY K-6G的最大吸附量分别为116.62,80.16和103.86 mg/g;5次循环使用后,HF-APT-DDF脱色率仍在80%以上;无机盐离子对吸附性能的影响从大到小为PO_(4)^(3-)>CO_(3)^(2-)>SO_(4)^(2-)>NO_(3)^(-)>Cl^(-);HF-APT-DDF对染料的吸附是自发的放热过程,遵循准二级动力学模型和Langmuir等温吸附模型。

两性纤维素多孔凝胶球的制备及其动态吸附性能

用于废水处理的多孔凝胶球存在制备工艺繁琐,吸附种类单一,吸附效率低等不足;为提高多孔凝胶球的性能,采用滴入相分离、酯化反应引入羧基及希夫碱反应引入氨基的化学改性方法,制备得到兼具高孔隙率、高力学性能和羧基/氨基活性基团的两性纤维素多孔凝胶球(ACM),并构建动态吸附柱装置以探究不同条件下ACM对染料的动态吸附性能。结果表明:通过降低染料初始质量浓度,增加填料高度和减慢进液流速的方式可有效提高吸附柱的动态吸附效率;0.8 g的ACM可处理7.5 L含染料的废水;对ACM的动态吸附过程进行动态模型拟合,其与Thomas和Yoon-Nelson模型的拟合程度高,表明吸附是均匀表面的单分子层吸附,动态吸附过程中存在2个或多个速率控制步骤,内部扩散和外部扩散均不是吸附过程中的限速步骤。基于ACM优异的分级孔结构、丰富的活性位点和低传质阻力等优势,认为ACM展现出良好的动态吸附性能,在印染废水处理方面有较大应用潜力。

The Adsorption Properties of TEMPO Oxidized Cellulose against the Mixture of Methylene Blue and Rhemazol Yellow FG

TEMPO/NaOCl/NaBr treatment significantly increased the number of negative charges on the cellulose surface.Two concentrations of NaOCl,5 and 30 mmol/g of cellulose,were used in this study.The number of carboxyl groups in the two cellulosic samples oxidized using TEMPO/NaOCl/NaBr was 0.5160 and 1.8461 mmol/g of cellulose,respectively.The oxidized cellulose samples treated with 5 and 30 mmol/g NaOCl exhibited higher crystallinity,at 81.15%and 80.14%,respectively,compared to untreated cellulose,which had a crystallinity of 75.95%.The pH effect indicated that the highest adsorption capacity for methylene blue was achieved under alkaline conditions(pH 9),while the highest adsorption capacity for rhemazol yellow FG was achieved under acidic conditions.The kinetic model of TEMPO-oxidized cellulose for methylene blue and rhemazol yellow FG conformed to the pseudo-second-order model.The initial concentration parameter revealed that the isotherm model for the adsorption of methylene blue and rhemazol yellow FG by TEMPO-oxidized cellulose conformed to the Langmuir model.The dye removal efficiencies for methylene blue and rhemazol yellow FG using TEMPOoxidized cellulose(30 mmol/g)were approximately 80.17%and 59.52%,respectively.These results demonstrate that TEMPO/NaOCl/NaBr-oxidized samples can effectively separate cationic and anionic dye mixtures.Furthermore,the use of TEMPO-oxidized cellulose showed good regeneration capability,maintaining more than 95%of its adsorption capacity after 8 cycles.

新型阴离子金属有机骨架化合物的合成及其对染料的吸附性能

以5,5′-(5,5-二氧化二苯并[b, d]噻吩-3,7-二基)二间苯二甲酸(H4DTPA)为有机配体,通过溶剂热合成方法构建一个结构新型的金属有机骨架化合物[NH_(2)(CH_(3))_(2)]·[Zn_(3)(DTPA)_(2)]·xsolvent.该化合物为1个{4,8}-连接的阴离子型的新型拓扑网状结构,具有良好的化学稳定性和热稳定性,并且对有机染料亚甲基蓝(MB)具有良好的选择性吸附性能.

无机阴离子对光催化燃料电池/过二硫酸盐协同体系影响的研究

本研究通过建立光催化燃料电池/过二硫酸盐(PFC/PS)体系降解活性艳兰染料(KN-R),考察了PFC/PS体系的催化活性及产电效能。结果表明,PFC与PS的耦合可大幅提升KN-R的脱色,处理120 min后,KN-R的脱色率达到99.37%。PFC协同PS体系可以提高电池性能,产生更多电能。与单独PFC相比,其最大输出功率密度(Pmax)从0.0003 m W/cm^(2)增加到0.0012 m W/cm^(2)。水中常见无机阴离子对PFC/PS协同体系降解KN-R及产电性能具有一定的促进作用。

花生壳粉生物吸附水溶液中阴离子染料的研究

An untried,low cost,locally available biosorbent for its anionic dye removal capacity from aqueous solution was investigated.Powder prepared from peanut hull had been used for biosorption of three anionic dyes,amaranth (Am),sunset yellow (SY) and fast green FCF (FG).The effects of various experimental parameters (e.g.initial pH and dye concentration,sorbent dosage,particle size,ion strength,contact time etc.) were examined and optimal experimental conditions were decided.At initial pH 2.0,three dyes studied could be removed effectively.When the dye concentration was 50 mg·L -1 ,the percentages of dyes sorbed was 95.5% in Am,91.3% in SY and 94.98% in FG,respectively.The ratios of dyes sorbed had neared maximum values in all three dyes when sorbent dose of 5.0 g·L -1 and the sorbent particle size in 80～100 mesh was used.The increasing the ion strength of solution caused the decrease in biosorption percentages of dyes.The equilibrium values arrived at about 36 hour for all three dyes.The isothermal data of biosorption followed the Langmuir and Freundlich models.The biosorption processes conformed the pseudo-first-order rate kinetics.The results indicated that powdered peanut hull was an attractive candidate for removing anionic dyes from dye wastewater.

钢渣对阴离子染料刚果红的吸附特性和机理

研究了钢渣对阴离子染料刚果红的吸附,并考察了初始刚果红浓度、钢渣投加量、钢渣粒径等因素对吸附过程的影响.试验条件下,钢渣可以吸附去除95%以上的刚果红,且吸附过程不受pH值和温度的影响.钢渣单位吸附量随初始刚果红浓度的增加而增加,随钢渣投加量、钢渣粒径的增大而减少.钢渣吸附处理刚果红过程符合准二级吸附速率方程及Freundlich等温吸附方程.对比试验发现钢渣对阳离子孔雀石绿染料的吸附效果优于阴离子刚果红染料,但对同为阳离子染料的亚甲基蓝吸附效果却很差.电镜扫描(SEM)及红外光谱(FTIR)分析进一步表明,钢渣吸附处理阴、阳离子染料的效果,与染料在钢渣表面的结合方式密切相关,结晶体的形成有利于染料分子的吸附.

氢氧化镁对水溶性阴离子染料废水脱色的研究

本文研究了氢氧化镁对水溶性阴离子染料模拟废水的脱色规律及机理.结果表明镁盐法具有优异的脱色效果.例如,染料浓度100mg·l^(-1),镁盐投加量1000mg·1^(-1),用CaO调至pH10.9—11.5,十种被研究的水溶性阴离子染料的脱色平均值在99%以上.吸附机理属于离子吸附.

氢氧化镁改性硅藻土对阴离子染料的吸附性能研究(英文)

对硅藻土进行氢氧化镁改性以提高它对印染废水中染料的吸附性能。采用原位沉淀法由MgCl2及NaOH在硅藻土上制备了氢氧化镁,并用SEM、XRD对改性材料进行了表征;用分光光度法研究了它对阴离子染料的吸附性能。结果显示:改性硅藻土的染料吸附能力比原硅藻土及氢氧化镁都高;染料的吸附等温线采用Langmuir及Freundlich模型拟合,结果表明改性硅藻土对染料的吸附更符合Freundlich模型。

苤蓝皮生物吸附去除水体中的阴离子染料

用低值的地产苤蓝皮材料作为生物吸附剂去除水体中的三种阴离子染料苋菜红、日落黄、亮绿,研究了pH值、吸附剂量、染料浓度、吸附剂粒径、离子强度、吸附时间等对吸附的影响,确定了最佳吸附条件.结果表明:三种染料在pH值为2时去除率较高;吸附在36h达到平衡.吸附等温线符合Langmuir模式,吸附过程符合Langergren准一级动力学方程.

农副产品制备纤维素强阴离子交换剂

麦杆、荞麦皮、锯末、稻壳等含约35%～50%的纤维素[1,2]. 目前大多被农民烧掉,污染环境,浪费了资源. Hwang等[3]研究了由纤维素制备的吸附剂对染料废水的处理. Maeda等[4]报道了纤维素粉末阴离子交换剂对阴离子染料的吸附,其吸附容量为活性炭的50～150倍. 古田等[5]利用棉纱纤维和丙烯酰胺接枝共聚,制成弱阴离子交换剂,研究了它对阴离子染料的脱色性能. 虽然有关纤维素季铵盐衍生物的制备已有报道[6],但农副产品纤维素强阴离子交换剂的制备未见报道. 我们用麦杆、荞麦皮、锯末、稻壳的纤维素为基质,采用醚化后季铵化的方法制备了强阴离子交换剂,测定了吸附和再生性能,发现其对印刷厂染料废水有良好的脱色效果.

新生态MnO_2对水溶性阴离子染料废水的脱色研究

以各种水溶性染料,包括直接染料、酸性媒介染料、活性染料的废水为实验对象,系统研究了新生态MnO2在染料废水脱色过程中的作用。结果表明,受试染料的脱色效果均十分显著,最佳pH≤2.5,脱色作用的机理在于MnO2的表面羟基在酸性条件下发生质子化,可以与阴离子染料以库仑力结合而将其吸附除去。

多种因素对MIL-101(Cr)选择性吸附水溶液中染料的影响

在多种条件下研究了金属有机框架MIL-101(Cr)对阳离子型染料(亚甲基蓝、罗丹明B)和阴离子型染料(甲基橙、酸性铬蓝K)的吸附性质,主要研究了MIL-101(Cr)对亚甲基蓝和甲基橙的选择性吸附作用。结果表明,中性环境下无论在单组分还是双组分体系中MIL-101(Cr)对阴离子型染料的吸附能力均大于对阳离子型的吸附能力。在p H=3,T=300 K的条件下,选择性系数β可达5.9,但随着p H的增加,选择性系数逐渐降低。相比之下,温度对吸附的选择性影响不大。选择性吸附的机理可以解释为:由于表面带正电荷,MIL-101(Cr)对阴离子型染料产生静电吸引作用;相反,对阳离子型染料的排斥作用而降低了其吸附能力。另外,乙二胺改性提高了MIL-101(Cr)对阴离子型染料的选择吸附性能,而草酸改性降低了选择吸附性。

新生态MnO_2吸附法处理水溶性阴离子染料废水的研究

研究了各种水溶性阴离子染料在新生态 Mn O2 表面的脱色作用。结果表明 ,9种不同模拟染料废水 (包括直接染料、酸性媒介染料、活性染料 )的脱色效果均十分显著 ,且脱色过程受 p H的影响较大。另外 ,通过 CHN元素分析、差热分析、紫外光谱及滴定分析等测试手段 ,初步认为在酸性介质下 ,新生 Mn O2 质子化的表面可以吸附阴离子型染料 ,从而将其去除。

阴离子型有机化合物在LDHs上的动力学和热力学研究

考察了水滑石焙烧产物MgAl-LDO吸附3种阴离子染料Acid Red88（AR88）、Acid Orange 3（AO3）、Acid Violet90（AV90）~程中的热力学和动力学机理．并在不同温度下探究该吸附过程的热力学参数。实验结果表明：MgAl-LDO对染料阴离子的吸附过程复合Langmuir吸附等温模型。且为自发、放热的过程。3种染料在MgAl-LDO上的吸附过程均符合准二级反应动力学模型，且该吸附过程是由MgAl-LDO与阴离子染料之间的反应速率控制而不是两者之间的扩散作用。计算所得的吉布斯自由能绝对值在7～15kJ·mol^-1．这主要是由染料阴离子与MgAl-LDHs层板的氢键作用产生，结合Materials Studio5．5软件模拟染料分子在MgAl-LDHs上的排列分布，推测MgAl-LDO对阴离子染料的吸附机理是表面吸附（占优势）与层间插层的协同作用。