Advanced Materials Research Vols. 781-784

Abstract: This paper describes the pyrolysis and combustion characteristics of PVC and PP from municipal solid waste applying the non-isothermal thermogravimetric analysis, the apparent activation energy and the pre-exponential factor were obtained by kinetics analysis. There is one phase in the pyrolysis of PP, which is volatile release at 281-489 °C. While, the process of PP combustion consists of one phase which is volatile release and combustion. There are two phases that are different volatile release in the pyrolysis of PVC. In the process of PVC combustion, there are two phase, the first is part of volatile release and combustion, the second is the other volatile release and fixed carbon combustion. It has been found that compensation effect exists in PP and PVC pyrolysis and combustion with the variation of oxygen concentration.

Abstract: A power plant in Hebei province aimed to use sodium hypochlorite as fungicide for the circulating water in its seawater electrolysis system by recycling desalination brine. The feasibility of this process was intensively studied using water quality analysis, electrochemical corrosion tests, and dynamic simulation tests. The results showed that this process is more efficient than that using seawater and would not aggravate the corrosion problem that is present in the current system. Scale produced by the electrolysis can be completely removed by acid-washing.

Abstract: Advantages and disadvantages of natural shields in a very low level waste (VLLW) disposal area were studied with regard to the adsorption and fixation capability of the natural shields against radioactive elements Uranium, Strontium and Cesium, with the understanding of the hydrogeological and geochemical characteristics of the surrounding area. Necessity of establishing geochemical engineering shield in the disposal area is discussed based on the understanding of the inadequacy of the natural shields against Uranium and Strontium. A physical chemistry model involving three-fold of shields suitable for the disposal area is proposed with integrated consideration of the results from efficacy and endurance experiments on the natural shield.

Abstract: Obstruction by fats, oil and grease (FOG) clogs in sewer pipelines results in high building maintenance costs. FOG in wastewater poses threats to properties and causes pollution of waterways and groundwater. A survey was carried out among residential households in the suburban township of Bandar Baru Bangi, Malaysia, to identify domestic practices in the handling and management of kitchen wastes. Improper practices in the disposal of kitchen wastes containing FOG is found to be the major cause of FOG accumulation in sewer pipes and drains. Preventive practices in the management of FOG in domestic kitchen waste should be the first line of solutions in mitigating FOG.

Abstract: PEAm-TMC/PDMS/PVC composite hollow fiber membrane for CO₂ separation was developed through interfacial polymerization (IP) on the PDMS pre-coated inner surface of PVC hollow fiber. Polyetheramine (PEAm) and Trimesoyl chloride (TMC) were selected as aqueous monomer and organic monomer, respectively. SEM observation result shows that the thickness of PEAm-TMC IP layer is about 215 nm. The effects of monomer concentrations and acid acceptor concentration on the membrane performance were investigated. The results shows that the CO₂ permeance decareses and CO₂/N₂ selectivity increases with the increasing concentrations of PEAm, TMC and Na₂CO₃. At 0.12 MPa, the composite hollow fiber membrane possesses a very high CO₂ permeance of 964 GPU and CO₂/N₂ selectivity of 40.6.

Abstract: Sequencing Batch Reactor (SBR) was investigated for the treatment of liquor wastewater in this paper. This study includes the test of start-up of the SBR, running of the reactor by treating the wastewater. During the start-up process the activated sludge was cultured and acclimated. After acclimation the removal efficiency of COD_cr can reach around 99%. Following investigations were focused on evaluation of the treatment efficiency and the reactive cycle during running the SBR. The experimental results showed that running parameters of SBR reaction system were Fill 0.5 h, React 10.0 h, Settle 2.0~2.5 h, Drain 0.5h, Idle 4.0h. Under these conditions the removal rate of COD_cr can reach 99%. So the performance of SBR for the wastewater was satisfactory as the wastewater had 1400~2000mg/l of COD_cr. The cyclic operation of SBR used in this study proved more effective in treating the wastewater.

Abstract: The glyphosate solution, sodium chloride and phosphate solid are separated concurrently by using different mixed solvent extraction processing from glyphosate production wastewater. Among them, ethanol-acetone is the best solvent extraction agent. In glyphosate solution after treatment, glyphosate content is 6.14 %, meanwhile, the content of sodium chloride and phosphate is rather low. So, it can be used as glyphosate agent production. The content of sodium chloride is up to 98 % after recrystallization, which can be as the raw material of chlor-alkai production. When the mother liquor of recrystallization combined with the original wastewater, the glyphosate can be close to the maximum recovery.

Abstract: The effects of red mud on growth of Alternanthera philoxeroides were examined. A. philoxeroides were planted at density of five individuals/ (0.2*0.2 m²) in wastewater with five dosage (0, 2, 5, 7 and 10 g/L) of red mud, and the experiment was carried out from December, 2012 to January, 2013. Our results revealed that it showed significant effects (p<0.05) of treatment by-red mud dosage on internode numbers before and after processing; significant differences were also shown in leaf numbers under red mud concentration of 10g/L comparing with 0 and 5 g/L. Also, stem diameter had a significant difference between 10 g/L and 0g/L of red mud concentrations. Leaves fell off a lot, and root-shoot ratio was only 0.2-0.3, significantly lower than the wild free state. These results suggested that the growth of A. philoxeroides used for sewage treatment added red mud for auxiliary were affected by red mud. By influencing the elongation or increase of some traits, a relatively higher concentration of red mud could slow down their growth.

Abstract: Sodium acetate has been separated and recycled in waste liquid from production by the process of precipitation, filtration, washing, concentration, crystallization, recrystallization and drying. The recycling of sodium acetate can be completely achieved by reuse hot water and liquor produced during concentrated and crystallization process respectively. Product quality of sodium acetate accords with national standard GB/T 693-1996 chemical pure grade. In the paper, the involved method of the waste water treatment has the characteristics of simple process, convenient operation, less investment and high return. Then, energy conservation and emissions reduction can be achieved when the technological process is used. Therefore, the recycling technology is suitable for industrialized production.

Abstract: Rice husk charcoal, a kind of new environmentally friendly biomass materials, which is made from rice husk under anaerobic combustion at 300°C, has been increasingly applied to remedy some polluted sites. Rice husk charcoal was employed to investigate adsorption of ammonium in simulated waste water, using once balance method. It is found that ammonium nitrogen in water can be rapidly adsorbed by rice husk charcoal in 2 min with maximum sorption capacity of 2.6 mg/g (Langmuir isotherm adsorption model). The n value of 1.2 in Freundlich isotherm model indicates that the absorbent is very suitable for rapid removal of ammonium from water. In addition, quasi-second order kinetic equation is well suited to describe ammonium absorption with time (P<0.01). The adsorption mechanism is supposed that rice husk charcoal firstly imbibes in water and much swells, and then ammonium ion diffuses into the micro pore structure and redistributes upon a steady state.