Advanced Materials Research Vols. 233-235

Abstract: Novel netlike nano-TiO₂ was successfully prepared using polylatic acid (PLA) as a new template, and in particular, it was recyclable as photocatalyst. The products obtained at various temperatures were characterized by scanning electron microscope (SEM), transmission electron microscope (TEM) and powder X-ray diffraction (XRD). Besides, the products have an excellent photocatalysis to methyl orange (MO) and methylene blue (MB).

Abstract: Poly (ethylene terephthalate) (PET) wastes were depolymerised using excess ethylene glycol (EG) in the presence of zinc acetate as transesterificaion catalyst. Influences of particle size, reaction temperature, weight ratio of ethylene glycol (EG) to PET and weight ratio of catalyst to PET on the yield of bis(hydroxyethyl terephthalate)(BHET) were investigated. The kinetics of glycolysis of PET in EG could be interpreted by the shrinking-core model of chemical reaction control, the activation energy of the glycolysis was 133 KJ/mol. The glycolysis product was analyzed and identified by FTIR and Element analysis.

Abstract: Precipitated silica was prepared by the hydrolysis of silicon tetrachloride in a dilute solution of soluble glass. In order to identify the optimal synthesis conditions of preparing silica powder with the good dispersivity and uniformity, technical parameters such as volumes of polyethylene glycol(PEG) and anhydrous ethanol, reaction temperature, final solution pH and the concentration of soluble glass were investigated. Products were characterized by scan electron microscopy(SEM),transmission electron microscopy(TEM), infrared spectroscopy(IR), x-ray diffraction(XRD) and laser nano-particle size analyzer. Under the optimal formation condition, amorphous silica particles with average diameters of 284nm and irregular-shaped morphology were obtained.

Abstract: Chitosan is a kind of natural, non-toxic and harmless substance. After its amino-group protonizing, it can form a cationic polymer which has excellent coagulation/flocculation properties. The application of chitosan in potable water treatment for the removal of particulates and dissolved organics has been studied extensively in the last decade. In order to further understand the specific property of chitosan applied in drinking water treatment, this paper introduces the effect of molecule weight and deacetylation of chitosan on coagulation/flocculation and coagulation/flocculation mechanism in drinking water treatment, gives an overview of chitosan characteristics of removal of suspend solids, organics and bacteria in water, particularly, describes the relationship between the removal efficiency of above impurities by chitosan and pH, dosage of chitosan.

Abstract: Aiming at the difficulties of aurum leaching from arsenic gold ore, the behavior of arsenic and aurum leaching by the roasting pretreatment of arsenic gold ore is discussed. The result indicates as the following: the rate of aurum extraction is only 14.16% to this kind of refractory gold ore by choosing normal method of aurum extraction. However, the rate of fixing arsenic is up to 95.77% and the aurum extraction rate is 78.45% through the pretreatment of fixing arsenic roasting under optimum roasting conditions like adding amount of CaCO₃ by 3%, roasting temperature 650°C and roasting time 4 hours. The result is satisfactory.

Abstract: In this corrosion test, simulated brine is used as corrosion medium, added different concentrations of aloe juice. Static weight-loss method is employed, meanwhile, we calculated corrosion rate of Q235 steel and researched on the corrosion inhibition effect of aloe in different temperatures. Results show that aloe is a good inhibitor, rate of corrosion inhibition can reach 80% or more and suitable for the temperature of work environment is less than 60 °C.

Abstract: The feasibility of using nonwoven polypropylene fiber (NWPP) as the filter media to treat oil-in-water emulsion was studied. Both static adsorption experiments and dynamic filtration in coalescence bed were made. Due to the hydrophobic property of NWPP, the oil adsorption happened immediately when contacted with NWPP. The equilibrium was achieved after 50min adsorption. The Freundlich isotherm fits the experimental data well. The data was analyzed with three adsorption kinetic models: the pseudo first order, second order adsorption kinetics as well as the intra-particle diffusion models. The results showed that the second order adsorption kinetic was more accurate to correlate the experimental data. After the dynamic filtration processes using 4.0g NWPP, the oil removal efficiency could achieve 95%. It also found that the low flow rates would be better to treat oil-in-water emulsion in dynamic condition using NWPP as the filter media.

Abstract: Under different sources of light, H₂O₂ was used as oxidant, Fe²⁺ or Fe³⁺ was used as catalyst to treat 3-Aminophenol wastewater. The results showed that the degradation of 3-Aminophenol solution was markedly accelerated in the conditions of 450W high pressure mercury lamp or strong sunshine. The degradation of 3-Aminophenol had better effects, under sunshine, and 1.5 mL FeSO₄·7H₂O solution with concentration 2.5 g·L^-1, 1.0 mL 6% H₂O₂, pH=3.5, were used. The degradation rate can reached to be as high as 99% after 40 min reaction.

Abstract: Huge storage tanks of Vinyl chloride monomer (VCM) are often regarded as major hazard installation because VCM is such a kind of flammable, explosive and toxic gas that leakage of liquid VCM would induce fire, explosion and toxic accidents. In this paper, index system of the safety of VCM storage tanks was established by analyzing four main factors including 18 indexes, based on accidents statistic and technology experience. Taking VCM storage tank in a petrochemical plant as a case, AHP-Fuzzy method was applied to achieve single VCM storage tank safety classification. The study could help companies develop preventive measures and emergency planning to reduce casualties and property losses.

Abstract: The removal efficiency and three-dimensional excitation emission matrix(3DEEM) fluorescence spectroscopic characterization of landfill leachate humus (HA and FA) in the Fenton-SBR process was studied. It was concluded that the combined Fenton-SBR process was available for effective removal of leachate humus, and the removal rates for HA and FA was 87.3% and 88.2%, respectively. The major fluorescence peaks observed in the leachate combined process was protein-like fluorescence peak a (Ex/Em=280nm/345nm), humic-like fluorescence peak b (Ex/Em=295/400nm), short excitation wavelength tryptophan-like fluorescence peak c (Ex/Em= 230nm/340nm) and ultraviolet band fulvic acid-like fluorescence peak d (Ex/Em=235nm/400nm). Types of fluorescence peak of HA and FA reduced and the intensities decreased after combined process treatment. The capability for removal of different components of humus was determined by the process units adopted.