洞庭湖湖区水资源保护规划

为了保护洞庭湖的水资源,通过对洞庭湖湖区水质现状及污染源的调查分析,确定了各湖区水质保护目标。根据洞庭湖区营养物质的输入、输出及平衡状况以及水污染源现状调查成果,分析了主要污染物现状排放量。针对水功能区的纳污能力分析成果,提出主要污染物入河控制量方案。在现有成果及相关资料基础上,根据湖区特征,针对存在的突出问题,提出了水资源保护目标及对策。

Novel SiO2 nanoparticle-decorated BiOCl nanosheets exhibiting high photocatalytic performances for the removal of organic pollutants

Novel SiO2/BiOCl composites were fabricated by decorating BiOCl nanosheets with SiO2 nanoparticles via a simple hydrothermal process. The as-prepared pure BiOCl and SiO2/BiOCl composites were intensively characterized by various techniques such as XRD, FT-IR, SEM/TEM, BET, UV-vis, DRS, XPS, and photocurrent measurements. The SiO2/BiOCl composite nanosheets displayed high photocatalytic activity and excellent stability in the degradation of organic pollutants such as phenol, bisphenol A (BPA), and rhodamine B (RhB). With respect to those over bare BiOCl, the degradation rates of RhB, BPA, and phenol over 1.88% SiO2/BiOCl increased 16.5%, 29.0%, and 38.7%, respectively. Radical capturing results suggested that h^+ is the major reactive species and that hydroxyl (·OH) and superoxide (·O2^-) radicals could also be involved in the degradation of organic pollutants. The enhanced photocatalytic performances of SiO2/BiOCl composites can be mainly attributed to the improved texture and the formation of intimate SiO2/BiOCl interfaces, which largely promoted the adsorption of organic pollutants, enhanced the light harvesting, and accelerated the separation of e^– and h^+.

Hydrogen producing water treatment through mesoporous TiO2 nanofibers with oriented nanocrystals

The development of well-defined TiO2 nanoarchitectures is a versatile strategy to achieve high-efficiency photocatalytic performance.In this study,mesoporous TiO2 nanofibers consisting of oriented nanocrystals were fabricated by a facile vapothermal-assisted topochemical transformation of preformed H-titanate nanobelts.The vapothermal temperature is crucial in tuning the microstructures and photocatalytic redox properties of the resulting mesoporous TiO2 nanofibers.The microstructures were characterized with XRD,TEM,XPS and nitrogen adsorption-desorption isotherms,etc.The photocatalytic activities were evaluated by photocatalytic oxidation of organic pollutant(Rhodamine B as an example)as well as photocatalytic reduction of water to generate hydrogen(H2).The nanofibers vapothermally treated at 150°C showed the highest photocatalytic activity in both oxidation and reduction reactions,2 times higher than that of P25.The oriented alignment and suitable mesoporosity in the resulting nanofiber architecture were crucial for enhancing photocatalytic performances.The oriented alignment of anisotropic anatase nanocrystals shall facilitate faster vectorial charge transportation along the nanofibers architecture.And,the suitable mesoporosity and high surface area would also effectively enhance the mass exchange during photocatalytic reactions.We also demonstrate that efficient energy-recovering photocatalytic water treatments could be accomplished by a cascading oxic-anoxic process where the dye is degraded in the oxic phase and hydrogen is generated in the successive anoxic phase.This study showcases a novel and facile method to fabricate mesoporous TiO2 nanofibers with high photocatalytic activity for both clean energy production and environmental purification.

Green synthesis of nickel nanoparticles using Ocimum sanctum and their application in dye and pollutant adsorption

Nickel nanoparticles as an eco-friendly adsorbent was biosynthesized using Ocimum sanctum leaf extract. The physiochemical properties of green synthesized nickel nanoparticles(Ni Gs) were characterized by UV–Vis spectroscopy(UV–Vis), Fourier Transform Infrared Spectroscopy(FTIR), X-ray diffraction(XRD), Scanning Electron Microscope(SEM) and Transmission Electron Microscope(TEM). Ni Gs were used as adsorbent for the removal of dyes such as crystal violet(CV), eosin Y(EY), orange II(OR) and anionic pollutant nitrate(NO3-), sulfate(SO42-) from aqueous solution. Adsorption capacity of Ni Gs was examined in batch modes at different p H, contact time, Ni G dosage, initial dye and pollutant concentration. The adsorption process was p H dependent and the adsorption capacity increased with increase in contact time and with that of Ni G dosage, whereas the adsorption capacity decreased at higher concentrations of dyes and pollutants. Maximum percentage removal of dyes and pollutants were observed at 40, 20,30, 10 and 10 mg·L-1initial concentration of CV, EY, OR, NO3-and SO42-respectively. The maximum adsorption capacities in Langmuir isotherm were found to be 0.454, 0.615, 0.273, 0.795 and 0.645 mg·g-1at p H 8, 3, 3, 7and 7 for CV, EY, OR, NO3-and SO42-respectively. The higher coef ficients of correlation in Langmuir isotherm suggested monolayer adsorption. The mean energies(E), 2.23, 3.53, 2.50, 5.00 and 3.16 k J·mol-1for CV, EY, OR, NO3-and SO42-respectively, calculated from the Dubinin–Radushkevich isotherm showed physical adsorption of adsorbate onto Ni Gs. Adsorption kinetics data was better fitted to pseudo-second-order kinetics with R2 N 0.870 for all dyes and pollutants. Ni Gs were found to be an effective adsorbent for the removal of dyes and pollutants from aqueous solution and can be applied to treat textile and tannery ef fluents.

Coating for Nano Super Soil-repellency of Cashmere Fabric

The nano-size metal oxide was prepared by the single-disperse technique on liquid phase, and formed sol dusters, its uniform film was covered on the surface of cashmere fibers by coating, and it had good oil repellency and water repellency. The results of IR（infrared） Spectrometer analysis revealed： The nano material combines through the strong bonds with the surface of cashmere fibers by the live groups. These analyses by SEM techniques showed that the nano material was distributed on the fiber surface even, and the nano material formed the strong peak of the regular crystal phase structure using the X-Ray Diffractometry （XRD） to analysis the fabric. The optimum techniques were selected by a series of experiments, coated cashmere fabric not only has preserved original properties of softness and comfort, but also has good properties of Bi-repellency function. Therefore, the technique will have potential appfication in engineers.

Sono-assisted preparation of magnetic ferroferric oxide/graphene oxide nanoparticles and application on dye removal

A simple ultrasound-assisted co-precipitation method was developed to prepare ferroferric oxide/graphene oxide magnetic nanoparticles(Fe_3O_4/CO MNPs).The hysteresis loop of Fe_3O_4/GO MNPs demonstrated that the sample was typical of superparamagnetic material.The samples were characterized by transmission electron microscope,and it is found that the particles are of small size.The Fe_3O_4/GO MNPs were further used as an adsorbent to remove Rhodamine B.The effects of initial pH of the solution,the dosage of adsorbent,temperature,contact time and the presence of interfering dyes on adsorption performance were investigated as well.The adsorption equilibrium and kinetics data were fitted well with the Freundlich isotherm and the pseudosecond-order kinetic model respectively.The adsorption process followed intra-particle diffusion model with more than one process affecting the adsorption of Rhodamine B.And the adsorption process was endothermic in nature.Furthermore,the magnetic composite with a high adsorption capacity of Rhodamine B could be effectively and simply separated using an external magnetic field.And the used particles could be regenerated and recycled easily.The magnetic composite could find potential applications for the removal of dye pollutants.

A Novel 3-D Nano-assembly Bacteria Based Biosensor for Enhanced Detection of Heavy Metal Pollutants

Nowadays, at a time of growing concern for sustainable development and compliance with environmental standards and legislation, the detection of heavy metal contaminants in environmental matrices represents a difficult but important task. The current major limitation lies in the poor detection limits of the targeted pollutant＇s trace concentrations by the available conventional techniques. In order to elaborate a novel ＂living＂ self assembled electrochemical 3-D biosensor, the authors propose a new concept to overcome this shortcoming. The advantages of the properties of polyelectrolyte-functionalized NBs （nanobeads） are combined along with the use of non covalently strongly bound micro-organisms. The designed 3-D biosensor is all the more promising as it has showed a significantly improved sensitivity. In fact, the detection limits of the tested heavy metals （cadmium and mercury） were as low as 1.0 × 10^-12 mol.L-1 and six to seven orders of magnitude lower than those provided by conventional 2-D biosensors. Furthermore, it is potentially applicable to a wide range of bioreceptor-pollutant detection systems.

2D/2D heterostructured photocatalyst: Rational design for energy and environmental applications

Two-dimensional/two-dimensional(2D/2D)hybrid nanomaterials have triggered extensive research in the photocatalytic field.The construction of emerging 2D/2D heterostructures can generate many intriguing advantages in exploring high-performance photocatalysts,mainly including preferable dimensionality design allowing large contact interface area,integrated merits of each 2D component and rapid charge separation by the heterojunction effect.Herein,we provide a comprehensive review of the recent progress on the fundamental aspects,general synthesis strategies(in situ growth and ex situ assembly)of 2D/2D heterostructured photocatalysts and highlight their applications in the fields of hydrogen evolution,CO2 reduction and removal of pollutants.Furthermore,the perspectives on the remaining challenges and future opportunities regarding the development of 2D/2D heterostructure photocatalysts are also presented.

Supported noble metal nanoparticles as photo/sono-catalysts for synthesis of chemicals and degradation of pollutants

This review summarizes the utilization of supported noble metal nanoparticles (such as Au/TiO2, Au/ZrO2, Ag/AgCl) as efficient photo/sono-catalysts for the selective synthesis of chemicals and degradation of environmental pollutants. Supported noble metal nanoparticles could efficiently catalyze the conversion of solar energy into chemical energy. Under UV/visible light irradiation, important chemical transformations such as the oxidation of alcohols to carbonyl compounds, the oxidation of thiol to disulfide, the oxidation of benzene to phenol, and the reduction of nitroaromatic compounds to form aromatic azo compounds, are effectively achieved by supported noble metal nanoparticles. Under ultrasound irradiation, supported noble metal nanoparticles could efficiently catalyze the production of hydrogen from water. Moreover, various pollutants, including aldehydes, alcohols, acids, phenolic compounds, and dyes, can be effectively decomposed over supported noble metal nanoparticles under UV/visible light irradiation. Under ultrasound irradiation, pollutant molecules can also be completely degraded with supported noble metal nanoparticles as catalysts.

Magnetite/Reduced Graphene Oxide Nanocomposites： One Step Solvothermal Synthesis and Use as a Novel Platform for Removal of Dye Pollutants

A simple one step solvothermal strategy using non-toxic and cost-effective precursors has been developed to prepare magnetite/reduced graphene oxide （MRGO） nanocomposites for removal of dye pollutants. Taking advantage of the combined benefits of graphene and magnetic nanoparticles, these MRGO nanocomposites exhibit excellent removal efficiency （over 91% for rhodamine B and over 94% for malachite green） and rapid separation from aqueous solution by an external magnetic field. Interestingly, the performance of the MRGO composites is strongly dependent on both the loading of Fe304 and the pH value. In addition, the adsorption behavior of this new adsorbent fits well with the Freundlich isotherm and the pseudo-second-order kinetic model. In further applications, real samples--including industrial waste water and lake water--have been treated using the MRGO composites. All the results demonstrate that the MRGO composites are effective adsorbents for removal of dye pollutants and thus could provide a new platform for dye decontamination.

PbCrO_4 yellow-pigment nanorods: An efficient and stable visible-light-active photocatalyst for O_2 evolution and photodegradation

Here, PbCrO4 nanorods, a commonly used and low-cost yellow pigment, was synthesized via a simple pre-cipitation reaction and can serve as a highly efficient oxygen production and photodegradation photocatalyst. The obtained PbCrO4 nanorods exhibit excellent stability and pho-tocatalytic performance for O2 evolution from water. The production rate is approximately 314.0μmol h^-1 g^-1 under visible light, and the quantum efficiency is approximately 2.16% at 420±10 nm and 0.05% at 600±10 nm. In addition, the PhCrO4 shows good degradation performance for methylene blue, methyl blue, methyl orange and phenol under visible-light irradiation. These results indicate that it is potential to fabricate an effective, robust PbCrO4 photocatalyst by trans-forming heavy-metal pollutants Pb（II） and Cr（VI） into a highly efficient O2 evolution and photodegradation material. This strategy which uses pollutant to produce clean energy and degrade contaminants is completely green and environmentally benign, and thus could be a promising way for practical environmental applications. Keywords： 02 evolution, pollutant, PbCrO4 nanorods, visible-light-active, photocatalyst