基于微波辅助脱除硫醇甲基锡废底料中的氯

以硫醇甲基锡废底料为研究对象,通过元素组成和XRD分析,结合废底料物性特征,设计了微波辅助干馏回收低沸点物质,残渣脱氯后用作锡冶炼精料的基本构思。实验研究表明：干馏可回收质量分数约15.86%的低沸点物质,同时可脱除约31.06%的氯。以残渣中氯含量为考察指标,系统研究了残渣与过氧化氢液固比、氧化静置时间、残渣与浓硫酸液固比、微波强化时间对氯脱除率的影响,结果表明：过氧化氢与残渣液固比为1∶5、氧化静置时间为30min、浓硫酸与残渣液固比为1∶3、微波强化时间为80min时,残渣中氯质量分数为0.59%,氯的脱除率可达到97.48%,满足企业锡冶炼精料氯质量分数＜0.8%要求。通过对微波浸取机制讨论以及残渣XRD、SEM的表征,初步对干馏残渣脱氯过程进行了机理分析,为硫醇甲基锡废底料中氯的脱除提供了理论依据,研究成果具有较好的应用前景。     

Surfactant free green synthesis of GOSiMa hybrid nanocomposite for charge storage application

Present work reveals the synthesis of graphene oxide-silica@magnesium oxide (GO-SiO₂@MgO)/(GOSiMa) hybrid nanocomposite by using a green sol-gel technique from its constituent precursors GO sheets, tetraethyl orthosilicate (TEOS) and magnesium chloride (MgCl₂). Broad ranges of characterization techniques like TEM, FESEM, EDAX, FTIR, XRD, DLS and BET are followed to investigate the hybrid composite. The cyclic voltammetry (CV) behaviour is studied at N₂ and O₂ atmosphere with Ag/AgCl electrode as a reference. The surface area of nanocomposites is found to be 107.59 m²/g with an average porosity value of 97.8602 Å. From the dielectric study, it is found that, synthesized GOSiMa nanocomposite has dielectric constant ε′ from 10² up to 2.5 × 10⁴ with the minimal dielectric loss ε′′ of ≤10² at all range of temperature 22 °C–185 °C and frequency range of 10³–10⁶ Hz. The effect of polarization and atomic rearrangements are the prime factors for enhancement of dielectric constant. Conductivities (σac) of this hybrid nanocomposite are measured as 8 × 10⁻³ S/m in the low-frequency region at 1 kHz and 1 × 10⁻² S/m at a high-frequency region of 2 MHz at a temperature of 160 °C for justifying the as-synthesized nanocomposite is a potential power electronics candidate for application in the charge storage device. The current work highlights the dielectric and charge storage potential of the prepared hybrid nanocomposite in a cost-effective and eco-friendly method.     

Microwave-assisted green synthesis of silver nanostructures

Over the past 25 years, microwave (MW) chemistry has moved from a laboratory curiosity to a well-established synthetic technique used in many academic and industrial laboratories around the world. Although the overwhelming number of MW-assisted applications today are still performed on a laboratory (mL) scale, we expect that this enabling technology may be used on a larger, perhaps even production, scale in conjunction with radio frequency or conventional heating. Microwave chemistry is based on two main principles, the dipolar mechanism and the electrical conductor mechanism. The dipolar mechanism occurs when, under a very high frequency electric field, a polar molecule attempts to follow the field in the same alignment. When this happens, the molecules release enough heat to drive the reaction forward. In the second mechanism, the irradiated sample is an electrical conductor and the charge carriers, ions and electrons, move through the material under the influence of the electric field and lead to polarization within the sample. These induced currents and any electrical resistance will heat the sample. This Account summarizes a microwave (MW)-assisted synthetic approach for producing silver nanostructures. MW heating has received considerable attention as a promising new method for the one-pot synthesis of metallic nanostructures in solutions. Researchers have successfully demonstrated the application of this method in the preparation of silver (Ag), gold (Au), platinum (Pt), and gold-palladium (Au-Pd) nanostructures. MW heating conditions allow not only for the preparation of spherical nanoparticles within a few minutes but also for the formation of single crystalline polygonal plates, sheets, rods, wires, tubes, and dendrites. The morphologies and sizes of the nanostructures can be controlled by changing various experimental parameters, such as the concentration of metallic salt precursors, the surfactant polymers, the chain length of the surfactant polymers, the solvents, and the operation reaction temperature. In general, nanostructures with smaller sizes, narrower size distributions, and a higher degree of crystallization have been obtained more consistently via MW heating than by heating with a conventional oil-bath. The use of microwaves to heat samples is a viable avenue for the greener synthesis of nanomaterials and provides several desirable features such as shorter reaction times, reduced energy consumption, and better product yields.     

Microwave-assisted green synthesis of Ag/reduced graphene oxide nanocomposite as a surface-enhanced Raman scattering substrate with high uniformity

A nanocomposite of silver nanoparticles/reduced graphene oxide (Ag/rGO) has been fabricated as a surface-enhanced Raman scattering (SERS) substrate owing to the large surface area and two-dimensional nanosheet structure of rGO. A facile and rapid microwave-assisted green route has been used for the formation of Ag nanoparticles and the reduction of graphene oxide simultaneously with L-arginine as the reducing agent. By increasing the cycle number of microwave irradiation from 1 and 4 to 8, the mean diameters of Ag nanoparticles deposited on the surface of rGO increased from 10.3 ± 4.6 and 21.4 ± 10.5 to 41.1 ± 12.6 nm. The SERS performance of Ag/rGO nanocomposite was examined using the common Raman reporter molecule 4-aminothiophenol (4-ATP). It was found that the Raman intensity of 4-ATP could be significantly enhanced by increasing the size and content of silver nanoparticles deposited on rGO. Although the Raman intensities of D-band and G-band of rGO were also enhanced simultaneously by the deposited Ag nanoparticles which limited the further improvement of SERS detection sensitivity, the detectable concentration of 4-ATP with Ag/rGO nanocomposite as the SERS substrate still could be lowered to be 10⁻¹⁰ M and the enhancement factor could be increased to 1.27 × 10¹⁰. Furthermore, it was also achievable to lower the relative standard deviation (RSD) values of the Raman intensities to below 5%. This revealed that the Ag/rGO nanocomposite obtained in this work could be used as a SERS substrate with high sensitivity and homogeneity.     

Microwave-assisted synthesis of hybrid colloids for design of conducting films

We report synthesis of colloids with polymer core and inorganic shell consisting of silver nanoparticles (AgNPs) which can be used as building blocks for the preparation of conducting composite films. Polymer colloids based on copolymer of styrene and butyl acrylate with variable film formation temperature and functional surface have been prepared by surfactant-free emulsion polymerization. Polymer particles with average size between 140 nm and 220 nm and narrow size distribution were used as templates for deposition of AgNPs by microwave-assisted reduction of silver precursors in aqueous medium. The loading of the AgNPs on the polymer particle surface has been increased up to 60 wt.-%. Obtained hybrid colloids were used for preparation of composite films. The electrical conductivity of the composite films starts to increase if the AgNPs loading on the polymer particle surface is above 20 wt.-%.     

废水中除铜研究的最新进展

随着铜在工业生产中的广泛应用,铜污染废水的排放量逐渐增加,由于溶解性铜的生物毒性,铜污染废水的处理日益引起人们的重视。针对近五年来对废水中铜去除的研究,文章介绍了沉淀法、吸附法、离子交换法、电化学法,并对已有文献中的技术特点进行了简要总结与分析。对水体中除铜的未来发展方向进行了分析。分析表明,结合原始水质特点,多种方法的工艺组合是从水体中去除铜的未来重点研究方向之一。     

Tannin-based adsorbents from green tea for removal of monoaromatic hydrocarbons in water: Preliminary investigations

In this study, we report the adsorption of benzene and toluene from water using rarely reported tannin adsorbents. Tannin gel and tannin powder were synthesized by adding formaldehyde to green tea extract, while iron nanoparticles were synthesized by the addition of FeSO₄?·?7H₂O. The surface morphology of the synthesized adsorbents was determined using SEM and FTIR prior to application to contaminated water. The results show up to 88% removal of benzene and toluene in a batch system after 30?min of reaction time, with a higher rate of removal of toluene compared to benzene. A low pH value of 2 had an adverse effect on the tannin gel, reducing the total adsorption of benzene to approx. 37.5%. On the other hand, iron nanoparticles were least affected by the pH with an adsorption of 62.9% for benzene and 83.3% for toluene.     

微波辅助废旧PET聚酯解聚反应研究

采用微波辅助加热的方式研究了回收PET聚酯的乙二醇解聚反应,并对比了相同催化作用下常规加热条件下的解聚反应,对解聚反应产物BHET进行了熔点测定和IFTIR分析.结果显示,两种方法下控制解聚反应至PET聚酯完全转化时单体BHET的收率相差不大,微波辅助条件下单体的收率略高,但是反应时间大大缩短.反应物PET与EG在1:...     

Adsorption and photocatalysis of colour removal from waste water using flyash and sunlight

Adsorption of dyes viz. thionine, eosin Y and rhodamine B on flyash has been investigated as a function of flyash and dye concentrations, contact time and pH. Photodegradation of dyes has been achieved by illuminating the reacting system containing dye and flyash with visible light.     

The use of dyestuff-treated rice hulls for removal of heavy metals from waste water

Rice hulls, when coated with the reactive dye of Procion Red or Procion Yellow, was found to be highly effective for removal of many metal ions from aqueous solutions both in batch and column method. When 120–130 ppm solutions were used, quantitative removal could be achieved with Pb²⁺, Cd²⁺, and Hg²⁺. After the adsorption of metal ions, the substrate could be recovered almost completely by treating with dilute hydrochloric or nitric acid solution, and used repeatedly.     

Solar light triggered catalytic performance of graphene-CuO nanocomposite for waste water treatment

In this work, the effect of a new nanocomposite material on the photodegradation of methylene blue is demonstrated. The nanocomposite is synthesized by the combination of cupric oxide (CuO) with graphene nanoplatelets (GNPs) and characterized by XRD, FE-SEM, FTIR, Raman, and UV–vis spectroscopy. Interestingly, the inclusion of GNPs with CuO enhances the photocatalytic properties of nanocomposite without tweaking inherent properties such as the conductive nature of GNPs. Within 80 min of exposure to the solar light, a 99.44% photodegradation of methylene blue is achieved, which is much better than using CuO alone, for which the degradation is only 75%. The much-improved photocatalytic performance of the nanocomposite is a consequence of low bandgap energy of GCuO as well as the conducting nature of GNPs, that causes fast photo excitation of electrons and lengthens the recombination lifetime of charge carriers respectively.     

Non-equilibrium sorption modeling for boron removal from geothermal water using sorption-microfiltration hybrid method

In this study, the boron removal performance of a hybrid system composed of ground ion exchange resin particles coupled with a microfiltration separation unit was investigated. A non-equilibrium sorption modeling approach was introduced so as to understand the contributions of mass transfer resistances on the effluent stream concentration profiles, as well as on the resin loading scheme of this sorption-microfiltration hybrid system. This modeling approach allowed us to suggest new system operations and/or scale-up processes of sorption-microfiltration hybrid systems. In this study, the highly porous crosslinked boron selective chelating resins Diaion CRB02 and Dowex XUS 43594.00 containing N-methyl-glucamine group were used. Geothermal water that has high levels of boron was fed into the stirred cell element of the microfiltration system. Kinetic behaviour of boron selective resins for boron removal from geothermal water by the microfiltration system was evaluated to investigate the effects of resin particle size, resin concentration, and permeate flow rate.     

Nickel(Ⅱ) removal from water using silica-based hybrid adsorbents:Fabrication and adsorption kinetics

A series of novel silica-based hybrid adsorbents were prepared by the crosslinking reaction of N-[3-(trimethoxysilyl)propyl] ethylene diamine(TMSPEDA) with epichlorohydrin(ECH) via a sol–gel process.Fourier transform infrared(FTIR) spectra confirmed that the reaction occurred.TGA curves showed that the thermal stability of these hybrid adsorbents reached as high as 180 °C.As a typical example,the adsorption performance of nickel(II) ions onto an adsorbent(the volume ratio of TMSPEDA and ECH was 4:1) was explored.It was found that the adsorption of nickel(II) ions onto this adsorbent followed the Lagergren pseudo-second-order kinetic model.The investigation of the adsorption mechanism demonstrated that nickel(II) adsorption was chiefly controlled by diffusion–chemisorption,suggesting that more diffusion processes were involved in the adsorption of nickel(II) ions onto this type of adsorbents.Desorption experiment indicates that these hybrid adsorbents can be regenerated.These findings reveal that this type of silica-based hybrid adsorbent is promising in the separation and recovery of nickel(II) ions from Ni-containing wastewater or contaminated water.     

微波辐射技术直接法合成水处理剂PASP

可生物降解型水处理剂聚天冬氨酸(PASP)的制备有2种技术路线,分别为天冬氨酸单体直接聚合法和以四碳原子有机酸为初始原料的间接聚合法.以微波为辐射热源,根据微波聚合技术理论,应用直接聚合法合成出PASP.通过IR等技术表征聚合物为目标产品.同时研究了PASP的分子质量等因素对工业循环冷却水中CaCO3盐垢晶体的阻垢分解能力.     

Supermacroporous hybrid polymeric cryogels for efficient removal of metallic contaminants and microbes from water

A supermacroporous cryogel column of chitosan-dimethylaminoethyl methacrylate (DMAEMA)-magnetite has been synthesized. The cationic and magnetic properties of chitosan/DMAEMA and magnetite, respectively, allow the adhesion of metals and microbes to the matrix. The large interconnected pores (20–100 µm) with porosity greater than 85% of the cryogels facilitate fast water movement. At lab scale (approximately 2 mL bed volume), static binding capacity of 100% (load: 4.5 ppm arsenic and 2300 ppm chromium) and dynamic binding capacity of 65% for arsenic (load: 58 ppm) was observed. The binding capacity at pilot scale (approximately 300 mL bed volume) was found to be 11.5 mg arsenic and 14.22 mg chromium. There was 100% binding of microbes (Escherichia coli and Streptococci) both at lab and pilot scale. The results were propitious and indicated the suitability of cryogel filter as a single device for the removal of arsenic, chromium, and microbes in field samples.     

微波辐射合成对乙酰氨基酚的研究

以对氨基苯酚和乙酸酐为原料,以锌粉为抗氧化剂,以活性炭为脱色剂,以稀乙酸为反应介质,采用微波辐射技术合成对乙酰氨基酚。探索了不同反应条件对产率的影响。实验表明,当n(对氨基酚)∶n(乙酸酐)为1∶1.3,反应介质稀乙酸体积浓度为4%,微波辐射功率为500 W,反应时间为17 m in,反应温度为105℃时,产率可达82.1%。     

聚氯乙烯合成水洗酸回收

介绍了用泡沫筛板塔回收氯乙烯合成过程中产生的水洗酸的工艺流程。经过实际的生产调试,找出了适宜1万～1．6万t／a PVC生产要求的运行参数,取得了一定的经济效益,并减少了环境污染。