Ionic liquid pretreatment as an emerging approach for synthesis of a magnetic adsorbent derived from Broussonetia papyrifera leaves for dye removal

ABSTRACT

Broussonetia papyrifera leaves were successfully converted into new magnetic adsorbents, including pretreatment using ionic liquid and magnetization via a coprecipitation technology. The resultant magnetic adsorbent was characterized with infrared spectroscopy (IR), transmission electron microscopy, scanning electron microscopy, and X-ray diffraction. Then, it was selected to adsorb methylene blue from aqueous solutions. The adsorption behaviors could be described well by pseudo-second-order kinetic and Langmuir isotherm models. The thermodynamic analysis for adsorption displayed that the process was exothermic and feasible spontaneous. Moreover, it exhibited a well reusability in the regeneration test. This adsorbent might be an alternative candidate with the advantageous properties of simplicity, repeatability, and convenient separation for pollutant removal.     

用活性炭吸附强化超滤过程脱除废水中染料的研究(英文)

In this study, orange G dye was efficiently removed from aqueous solution by ultrafiltration (UF) mem-brane separation enhanced with activated carbon adsorption. The powdered activated carbon (PAC) was deposited onto the UF membrane surface, forming an intact filter cake. The enhanced UF process simultaneously exploited the high water permeation flux of porous membrane and the high adsorption ability of PAC toward dye molecules. The influencing factors on the dye removal were investigated. The results indicated that with sufficient PAC incor-poration, the formation of intact PAC filtration cake led to nearly complete rejection for dye solution under opti-mized dye concentration and operation pressure, without large sacrificing the permeation flux of the filtration process. Typically, the dye rejection ratio increased from 43.6% for single UF without adsorption to nearly 100% for the en-hanced UF process, achieving long time continuous treatment with water permeation flux of 47 L·m 2·h 1. The pre-sent study demonstrated that adsorption enhanced UF may be a feasible method for the dye wastewater treatment.     

Crosslinking of electrospun fibrous gelatin scaffolds for apatite mineralization

Fibrous gelatin scaffolds fabricated via electrospinning followed by crosslinking were used as substrates for apatite mineralization. Gelatin macromolecules were confined by their fibers and further restricted by the crosslinked structure while proper flexibility could be attained upon hydration. After 4 or 5 days of mineralization, partially carbonated hydroxyapatite was proved to deposit uniformly on the surface of the fibers. The property of the substrate, such as stiffness of the scaffolds and flexibility of macromolecules chain, was changed by different crosslinking ways. The influences of these properties on the formation of apatite were also investigated. Results showed that a relatively less rigid interface and more flexible chain acquired by glutaraldehyde solution crosslinking seemed to favor the nucleation of minerals and to reduce the size of the inorganic products. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

The synergistic performance of multiwalled carbon nanotubes and sepiolite nanoclays as flame retardants for unsaturated polyester

The synergistic effect on the thermal decomposition and heat release rate (HRR) in particular the peak heat release rate (PHRR) of unsaturated polyester (UP) resin blended with multiwalled carbon nanotubes (MWNTs) and sepiolite nanoclay was investigated using thermal gravimetric analysis (TGA), pyrolysis combustion flow calorimetery (PCFC) and the cone calorimetery. Initial microcalorimeter findings established a synergistic effect for ternary system comprising a 10:0.5 wt% mixture of sepiolite:MWNT, respectively, which resulted in a 40% reduction in heat release capacity (HRC). This result was also confirmed within the well‐established cone calorimeter by a 50% reduction in PHRR in contrast to unfilled UP. The mechanism behind this reduction is thought to be due to the bridging of the MWNTs between the sepiolite clay needles, creating a tight protective surface layer that reduces the MLR. TGA also confirmed the advantage of such a ternary system through a 36^°C shift in the onset decomposition temperature and an 11% increase in residual char. Copyright © 2010 John Wiley & Sons, Ltd.     

PDMDAAC改性高炉渣处理印染废水的研究

用聚二甲基二烯丙基氯化铵(PDMDAAC)改性高炉渣,研究了PDMDAAC改性高炉渣去除模拟印染废水中分散染料和活性染料的性能.结果表明,PDMDAAC改性高炉渣去除分散和活性染料的能力远大于原渣;研究了振荡时间、温度和pH对改性高炉渣处理效果的影响,结果表明,温度对去除效果影响很小,而振荡时间和pH的影响比较大.     

Deduction of a facile method to construct Antheraea mylitta silk fibroin/gelatin blend films for prospective biomedical applications

Blend films of two types (I and II) were prepared by mixing Antheraea mylitta silk fibroin (AMF) and gelatin solution in various blend ratios via the solution casting method. Two different crosslinkers, namely glutaraldehyde and genipin, were used during blend preparation. The structural characteristics and thermal properties of the blend films were examined by Fourier transform infrared (FTIR) spectroscopy, X‐ray diffraction (XRD), Thermogravimetric analysis (TGA) and Diffrential scanning calorimetery (DSC). The FTIR spectra showed conformational alterations in type I blend films while type II films attained high β‐sheet crystallinity. The XRD diffractograms presented a high degree of crystallinity in type II blend films compared to type I, which showed an almost amorphous structure. Further, thermal and biological studies were conducted on type II films. According to the TGA thermograms, the degradation temperature of the crosslinked blend films shifted compared to pure gelatin and pure AMF films. Partial miscibility of the two components was indicated by DSC thermograms of the blends. The high water uptake capacity of type II blend films was found to imitate hydrogel behaviour. The blend films did not show any toxicity in 3‐(4,5‐dimethylthiazol‐2‐yl)‐2,5‐diphenyl tetrazolium bromide (MTT) assay and supported L929 fibroblast cell spreading and proliferation. The biodegradation of the blend films was significantly faster than the pure silk film. © 2020 Society of Industrial Chemistry     

Modification of chitosan with cellulose and gelatin for the removal of Cu2+, Fe2+, and Pb2+ from oily wastewater

In this study, chitosan was modified with cellulose and gelatin for the removal of Cu²⁺, Fe²⁺, and Pb²⁺ from oily wastewater. Chitosan was characterized using Fourier-transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), and X-ray diffraction (XRD). Carbon (77.54%), hydrogen (10.30%), oxygen (8.89%), nitrogen (2.74%), and sulphur (0.53%) were found in the organic constitution of the oil utilized, according to elemental analysis. Despite the presence of other metal ions in the used oil and effluent, this study focused solely on Cu²⁺, Fe²⁺, and Pb²⁺. Studies on the removal of Cu²⁺, Fe²⁺, and Pb²⁺ from oily wastewater were conducted, and multiple effect factors such as temperature and pH, time and pH, solvent and pH, temperature and time, temperature and solvent, and time and solvent were evaluated. An adsorption study was performed to remove the heavy metals. The results revealed that the highest percentage removal of Cu²⁺ was 96.62 (pH = 7.52 and conductivity = −12 mV), of Fe²⁺ was 97.95 (pH = 6.30 and conductivity = +68 mV), and of Pb²⁺ was 98.86 (pH = 10.58 and conductivity = −170 mV). To analyze the impacts of experimental factors, experiments were developed using central composite design (CCD) based on response surface methodology (RSM).     

Effect of hydrotalcite on the swelling and mechanical behaviors for the hybrid nanocomposite hydrogels based on gelatin and hydrotalcite

A series of hybrid nanocomposite hydrogels, based on gelatin and intercalated hydrotalcite (IHT), crosslinked with glutaraldehyde, was prepared in this study. The microstructures of the IHT and sample gels were identified by X‐ray diffraction (XRD). Swelling behaviors and physical properties of these hybrid gels were investigated. XRD results indicated that exfoliation of IHT was achieved in the hybrid nanocomposite gels. The results indicated that adding a small amount of IHT could effectively decrease the swelling ratio of the hybrid gels, but adding excess IHT could increase the swelling ratio of the nanocomposite hybrid gels. The crosslinking densities (ρ_x) of the present gels varied with IHT content and swelling ratio of the gels. The drug release behaviors of these gels were also investigated. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 500–507, 2006     

吸附法处理废水中砷的研究现状及进展

水体中的砷严重危害到人体健康,寻求高效廉价的除砷技术已成为研究热点。吸附法因其简单易行、去除效果好、能回收废水中的砷、对环境不产生或很少产生二次污染,且吸附材料来源广泛、价格低廉、可重复使用备受人们关注。综述了当前国内外用不同吸附方法去除水中砷的研究进展,分析了各种方法的吸附性能和特点,提出生物质吸附剂和废弃物吸附剂应成为水体中砷去除的研发热点。     

Insight into the adsorption mechanism of cationic dye onto biosorbents derived from agricultural wastes

This study investigated the phenomenon and mechanism of adsorption of methylene green 5 (MG5) on three pristine biosorbents: golden shower pod (GS), coconut shell (CC), and orange peel (OP). The results showed that the biosorbents possessed low specific surface areas, but abundant functional groups. Adsorption was strongly affected by the solution’s pH and ionic strength. As revealed in the kinetic study, equilibrium was rapidly established, requiring low activation energies; a removal rate of 30%–87% was achieved within 1?min. The maximum Langmuir adsorption capacities at 30°C exhibited the following order: GS (106?mg/g)?>?OP (92?mg/g)?>?CC (59?mg/g). Thermodynamic experiments suggested that the adsorption occurred spontaneously (?ΔG°) and exothermically (?ΔH°). The primary adsorption mechanisms involved electrostatic attraction, hydrogen bonding formations, and n-π interaction. Thermogravimetric analysis (TGA) revealed that three biopolymer components (i.e., hemicellulose, cellulose, and lignin) played controlling roles in the adsorption process. Thus, these three agricultural residues can be considered potential low-cost adsorbents for efficient dye adsorption applications.     

纳米羟基磷灰石增强聚己内酯/明胶纤维膜的制备及其性能

引导组织再生膜在引导组织再生术中发挥着关键作用,高性能的引导组织再生膜能更好地促进组织再生修复。本文以纳米羟基磷灰石（n-HA）、聚己内酯（PCL）、明胶（Gel）为原料,通过静电纺丝法制备了不同含量n-HA增强的PCL/Gel/n-HA纤维膜,并对其形貌、组成、力学性能及降解性能进行了研究。SEM结果表明,纤维膜中的纤维形态良好,纤维直径大致分布于200～400nm之间,交联后纤维直径明显增加;TEM结果表明,n-HA较均匀分散在纤维中,随着n-HA含量的增加,n-HA在纤维膜表面发生聚集。力学测试结果表明,随着n-HA含量的增加显著提高了纤维膜的拉伸强度和断裂伸长率,当n-HA含量约为15%时,其拉伸强度和伸长率分别达到9.18MPa和180%。n-HA加入后,纤维膜的降解速率明显降低,n-HA含量约为15%的复合纤维膜体外降解12周以后约降解25%。本文制备的PCL/Gel/n-HA纤维膜的力学性能和降解速率能满足临床对引导组织再生膜的性能要求。     

Adsorptive removal of dye from real textile wastewater using graphene oxide produced via modifications of hummers method

Abstract

This work focused on producing different graphene oxide (GO) samples for further application in the adsorptive removal of dyes from real textile wastewater. Among all conditions tested, the sample produced using KMnO₄ and no sonication bath exhibited the best performance. Before the experiments using wastewater, kinetics and equilibrium of adsorption studies were performed with Methylene Blue (MB) dye. Experimental data showed the isotherm fitted the Freundlich model, and kinetic results fitted the pseudo-second order model. Theoretical q_max was 308.11?mg.g^?1 and over 90% removal of MB was reached in approximately 5?min. Although GO has been widely applied to remove cationic and anionic dyes from water, not many studies have presented GO as an adsorbent for real textile wastewater treatment. In 30?min, GO removed nearly 85% of turbidity and over 60% of color from a real sample, indicating that GO might be an excellent alternative to treat textile wastewater.     

皮革黑染色废液的处理

用“絮凝－吸附－沉淀”法对皮革黑染色废液进行处理。结果表明：脱色率大于９６％,ＣＯＤｃｒ去除率为９２．４％,达到了国标排放标准,令人满意。     

Dye removal from colored‐textile wastewater using chitosan‐PPI dendrimer hybrid as a biopolymer: Optimization,kinetic, and isotherm studies

Preparation of a biopolymer chitosan‐polypropylene imine (CS‐PPI) as a biocompatible adsorbent and its reactive textile dyes removal potential were performed. Chemical specifications of CS‐PPI were determined using Fourier transform infrared, ¹H‐NMR, and ¹³C‐NMR. The surface morphology of the CS‐PPI surface was characterized by scanning electron microscopy. Results confirmed that the linkages between the NH₂ groups of PPI dendrimer and carboxylic groups of modified Chitosan were accomplished chemically. Two textile reactive dyes, reactive black 5 (RB5) and reactive red 198 (RR198), were used as model compounds. A response surface methodology was applied to estimate the simple and combined effects of the operating variables, including pH, dye concentration, time contact, and temperature. Under the optimal values of process parameters, the dye removal performance of 97 and 99% was achieved for RB5 and RR198, respectively. Furthermore, the isotherm and kinetic models of dyes adsorption were performed. Adsorption data represented that both examined dye followed the Langmuir isotherm. The adsorption kinetics of both reactive dyes were satisfied by pseudo‐second order equation. Based on this study, CS‐PPI due to having high adsorption capacity (6250 mg/g for RB5 and 5882.35 mg/g for RR198), biocompatibility and ecofriendly properties might be a suitable adsorbent for removal of reactive dyes from colored solutions. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

Mineral waste from coal mining for removal of astrazon red dye from aqueous solutions

The use of mineral waste from coal mining (MWCM) as an adsorbent for the removal of astrazon red dye (AR) from aqueous solution was studied in detail. Batch adsorption experiments were carried out under varied conditions, such as different initial concentrations of AR, contact time, pH, temperature and calcination of the adsorbent. Investigations revealed that the maximum colour removal was observed for unbuffered solutions. MWCM calcinated at 400 °C (MWCM400) was more efficient for dye removal than samples calcinated at other temperatures. The adsorption isotherm of AR on MWCM400 was determined and correlated with the Langmuir and Freundlich models; the results indicated a better fit for the Langmuir model at all the temperatures studied. Kinetic data were fitted with both pseudo-first-order and pseudo-second-order kinetic models, and the data were found to follow the latter model more adequately. Calculated thermodynamic and kinetic parameters indicate a predominantly physisorption mechanism for the adsorption of AR onto MWCM400. The amount of AR adsorbed by MWCM400 per unit area was found to be two or three times greater than that by several comparable adsorbents.     

Adsorptive removal of alizarin dye from wastewater using maghemite nanoadsorbents

ABSTRACT

This is an investigation of the adsorptive removal of anthraquinone dyes, resembled by Alizarin, by utilizing maghemite iron oxide (γ-Fe₂O₃) nanoparticles in aqueous media. The adsorption process was affected by several parameters such as solution pH, adsorbent amount, contact time, and temperature. After optimizing the parameters affecting the adsorption, the process was successful in removing Alizarin dye with an efficiency exceeding 95%. Best adsorption results were achieved at a pH of 11 and contact time of 60 min. The adsorption was shown to follow the Langmuir model suggesting a monolayer and homogeneous coverage. The maximum adsorption capacity (q_m ) was found to be 23.2 mg/g at pH = 11. A thermodynamic study showed that the adsorption process is exothermic and spontaneous at room temperature. The Gibbs free energy of adsorption (-6.79 kJ/mol) obtained in this study suggests a physisorption process. This finding has facilitated the regeneration of the Fe₂O₃ nanocatalyst. Both NaOH and HNO₃ at dilute levels were tested for the regeneration of the nanocatalyst. Regeneration with HNO₃ was successful up to four successive removal cycles with an efficiency >80%. Photodegradation experiments utilizing a UV light were also successful in maximizing the adsorption removal efficiency. A sorption mechanism based on the results obtained in this work is also proposed.     

Preparing of novel fibrous ligand exchange adsorbent for rapid column-mode trace phosphate removal from water

We developed a potentially high-performance adsorbent for sustainable treatment of soluble inorganic trace phosphate from water by zirconium(IV) loaded bifunctional fibers. In the presence of common Cl⁻ and SO₄²⁻, phosphate adsorption was not adversely affected but slightly enhanced due to co-ion and Donnan invasion mechanism. Trace phosphorus (0.0143 mM) was also removed in presence of relatively high amounts of competing anions at high feed flow rate (850 h⁻¹). In competitive arsenate and phosphate adsorption, this novel adsorbent slightly preferred phosphate to arsenate. The adsorbent is reversible and keeps remaining functionality to further reuse in many cycles.     

Influence of cosurfactant in microemulsion systems for color removal from textile wastewater

Microemulsion systems have proved very efficient in color removal from textile wastewater using n‐butyl alcohol as cosurfactant. The cosurfactant has a very important role in microemulsified systems, as it is responsible for their stability, mainly in systems formed by ionic surfactants. Although very efficient, n‐butyl alcohol is partially soluble in water, which would permit its passage to the effluent. In this work, isoamyl and octyl alcohols, due to their lower solubility in water, were used as cosurfactants to evaluate their influence in color removal. The colorimetry system used was the CIE L*a*b* (CIELAB) color space and CIE L*a*b* color difference (ΔE*_ab). The wastewater used in this study was the reactive exhausted dye liquor from a dye house (first discharge) containing Procion Yellow H‐E4R (CI Reactive Yellow 84), Procion Blue H‐ERD (CI Reactive Blue 160) and Procion Red H‐E3B (CI Reactive Red 120). The obtained results were modeled using an experimental planning (the Scheffé net) and evaluated through isoresponse diagrams by correlation graphs between experimental values and those obtained by the models with an error lower than 4%. All the optimized systems were very efficient and more than 94% of the dyes contained in the effluent were removed. The microemulsion load capacity was determined using a synthetic solution containing, the same dyes present in the reactive exhausted dyebath, but 200 times concentrated, and the dyes extraction was more than 99.6%. By comparing n‐butyl, isoamyl and octyl alcohols, it was observed that the system using isoamyl alcohol presented slightly better color removal and much higher load capacity than the n‐butyl and octyl alcohols. Copyright © 2004 Society of Chemical Industry