Effect of dye-metal complexation on photocatalytic decomposition of the dyes on TiO_2 under visible irradiation

The photocatalytic degradation of dyes （Acid Chrome Blue K （ACBK） and Alizarin Red （AR）） with strong complexation ability was investigated in the presence of metal ions under visible light irradiation. It was found that, at low dye-metal ratio, the photodegradation of ACBK was markedly inhibited by the addition of high oxidative potential Cu2＋. However, at high dye-metal ratio, the presence of Cu2＋ enhanced the photodegradation of ACBK. The negtive effect of Cu2＋ on the photodegradation of AR was observed for all dyemetal ratios. The relative chemical inert Zn2＋ tended to enhance the photodegradation of both anionic dyes. The mechanism underlying the different effect of Cu2＋ was discussed from the different roles of surface-adsorbed and dye-coordinated Cu2＋ in the photodegradation of dyes.

Research on Some Brown Iron Complex Azo Dyes

Some novel 1:1 and 1 ：2 Fe complex azo dyes were synthesized in this study.The mass spectrum analysis of 1:1 and 1:2 Fe complex azo dyes is presented.Lightfastness,rubbing fastness and washing fastness of these metallized complex dyes were evaluated for use on wool.Results show that these dyes are of good lightfastness and satisfactory brown shades.

Preparation of Black Poly(Methyl Methacrylate-Ethyleneglycol Dimethacrylate) Microspheres Using Metallic Complex Dyes

In this study, we synthesized polymethyl methacrylate cross-linked microspheres and functionalized the surface of the microspheres with amine groups, and discussed the effect of functionalization and the change of the surface morphology of the microspheres. This research uses 1:2 metal composite acid dye to dye self-synthesized microspheres with uniform particle size, and successfully prepares black polymethyl methacrylate cross-linked microspheres, which are applied to spacer microspheres.

Review on transition metal compounds based counter electrode for dye-sensitized solar cells

Commercial application of the dye-sensitized solar cells（DSCs） depends on great improvement of the power conversion efficiency and reduction of the fabrication cost. Generally, developing low cost counter electrode catalysts to replace the expensive Pt counter electrode is a feasible path to reduce the production cost of DSCs. In this review article, we summarize the recent progress on the transition metal compound based counter electrode catalysts containing carbides, nitrides, oxides, sulfides, phosphide, selenides, borides, silicide, and telluride toward the regeneration of the traditional iodide redox couple.Moreover, the benefits and drawbacks of each kind of CE catalyst are discussed and the research directions to design new counter electrode catalysts in future research are also proposed.

Preparation and properties of chitosan–metal complex：Some factors influencing the adsorption capacity for dyes in aqueous solution

Chitosan–metal complexes have been widely studied in wastewater treatment, but there are still various factors in complex preparation which are collectively responsible for improving the adsorption capacity need to be further studied. Thus, this study investigates the factors affecting the adsorption ability of chitosan–metal complex adsorbents, including various kinds of metal centers, different metal salts and crosslinking degree. The results show that the chitosan–Fe（ Ⅲ） complex prepared by sulfate salts exhibited the best adsorption efficiency（100%） for various dyes in very short time duration（10 min）, and its maximum adsorption capacity achieved 349.22 mg/g. The anion of the metal salt which was used in preparation played an important role to enhance the adsorption ability of chitosan–metal complex. SO4^（2-） ions not only had the effect of crosslinking through electrostatic interaction with amine group of chitosan polymer, but also could facilitate the chelation of metal ions with chitosan polymer during the synthesis process.Additionally, the p H sensitivity and the sensitivity of ionic environment for chitosan–metal complex were analyzed. We hope that these factors affecting the adsorption of the chitosan–metal complex can help not only in optimizing its use but also in designing new chitosan–metal based complexes.

Activated carbon-hybridized and amine-modified polyacrylonitrile nanofibers toward ultrahigh and recyclable metal ion and dye adsorption from wastewater

Nanofibers with high specific surface area and chemical stability have broad prospects in the applications of adsorption.However,the adsorption capacity is limited by the scarcity of adsorption groups and storage space.Herein,the activated carbon-hybridized and amine-modified nanofibers are prepared by integrating activated carbon(AC)and polyacrylonitrile(PAN)via electrospinning method and the subsequent amination,which could provide additional storage space and adsorption groups for ultrahigh adsorption capability.Thus,the obtained amine-rich porous PAN nanofibers(APAN/AC)readily realized the ultrahigh adsorption capacity for metal ions and dyes in wastewater.Specifically,the adsorption capacity of APAN/AC nanofibers were 284 mg·g^(-1) for Cr(VI)and 248 mg·g^(-1) for methyl orange,which were almost 2 and 4 times than that of amine-modified nanofibers(APAN)and carbon-hybridized nanofibers(PAN/AC),respectively.Moreover,the AC inhibited the chain mobility of polymer matrix and thereby endowing APAN/AC nanofibers with excellent recyclability.The adsorption capability retained 80%after nine adsorption-desorption cycles.The adsorption kinetics and corresponding mechanism were further explored.This strategy combines the advantages of polymer nanofibers and AC,opening a new avenue for developing next-generation absorbent materials.

Strong enhancement of methylene blue removal from binary wastewater by in-situ ferrite process

Dye wastewater containing heavy metal ions is a common industrial effluent with complex physicochemical properties. The treatment of metal-dye binary wastewater is difficult. In this work, a novel in-situ ferrite process （IFP） was applied to treat Methylene Blue （MB）-Cu（II） binary wastewater, and the operational parameters were optimized for MB removal. Results showed that the optimum operating conditions were OH/M of 1.72, Cu2＋/Fe2＋ ratio of 1/2.5, reaction time of 90 min, aeration intensity of 320 mL/min, and reaction temperature of 40℃. Moreover, the presence of Ca2＋ and Mg2＋ moderately influenced the MB removal. Physical characterization results indicated that the precipitates yielded in IFP presented high surface area {232.50 m2/g） and a multi-porous structure. Based on the Langmuir model, the maximum adsorption capacity toward MB was 347.82 mg/g for the precipitates produced in IFP, which outperformed most other adsorbents. Furthermore, IFP rapidly sequestered MB with removal efficiency 5 to 10 times greater than that by general ferrite adsorption, which suggested a strong enhancement of MB removal by IFP. The MB removal process by IFP showed two different high removal stages, each with a corresponding removal mechanism. In the first brief stage （〈5 min）, the initial high MB removal （～95%） was achieved by predominantly electrostatic interactions. Then the sweep effect and encapsulation were dominant in the second longer stage.

A Facile Method for Dye and Heavy Metal Elimination by p H Sensitive Acid Activated Montmorillonite/Polyethersulfone Nanocomposite Membrane

Modified clay/polyethersulfone（PES） mixed matrix membranes（MMMs） were prepared by acid activated montmorillonite（AA-MMT） with different concentrations and used to eliminate dyes and remove heavy metals from aqueous solution. The morphology and physiochemical properties of prepared clay nanoparticles and MMMs were characterized using X-ray diffraction（XRD）, Fourier transform infrared（FTIR） spectroscopy, scanning electron microscopy（SEM）, enegy dispersive X-ray（EDX） spectroscopy, Brunauer-Emmett-Teller（BET） analysis, atomic force microscopy（AFM）, contact angle measurement and fouling studies. The filtration study showed that removal of dyes and heavy metals was strongly dependent on p H so that dyes with positive and negative charges showed different separation efficiency in acidic and alkaline conditions. The modified membranes possessed better heavy metal removal in acidic and alkaline p Hs. When the rejection of heavy metals was measured in an alkaline environment, it was observed that the rejection had a great increase compared to the neutral values for Zn^（2＋） and Ni^（2＋） ions, while rejection of Cu^（2＋） and Cd^（2＋） did not undergo significant changes. So it can be concluded that modified membranes show good selectivity for elimination of Zn^（2＋） and Ni^（2＋） ions with respect to other cations.