Advanced Materials Research Vols. 864-867

Abstract: The most shortage of heat-exchanger in crude oil stabilizer station was scaling. The forming of blockage has been confirmed, by the methods of chemical analysis, XRD diffraction and scanning electron microscopy (SEM) to analyse the qualitative and quantitative of it. The blockage is due to the impurity in oil. On one hand, the inorganic substances, mainly Si⁴⁺ and Al³⁺, adhere to the wall by chemical reaction. On the other hand, heavy oil, like asphaltenes, is eluted from flow and exacerbated the adsorption force. Thus, a group of organic and inorganic clogs has formed, which cause the scaling of heat-exchanger unit.

Abstract: The pot experiments were carried out to test planting of oil sunflower with the application of desulfurization gypsum in ameliorating sodic salinity soils. Results showed that exchangeable sodium pH values decreased significantly while soil salt content increased. The germination rate and yield of the sunflower increased significantly after desulfurization gypsum was applied, but excessive application of desulfurization gypsum inhibited germination and growth of the plant. There is the best improvement after application of 33.75(t·hm^-2) of desulfurization gypsum in the 0-20 cm surface layer of soils moderate in sodic salinity, such conditions are favorable for sunflower growth.

Abstract: The effect of aggregated floc circulation on membrane fouling in contact circulated coagulation-membrane filtration hybrid process for treatment of surface water was investigated in this study. In order to understand the floc characteristics, the floc formation, breakage and re-growth were monitored by Mastersizer 2000 under the coagulation dosage of 5, 10, 15 and 20mg/l. A contact circulated coagulation tests were carried out and the effluent was filtered by a dead-end micro-filtration with the hollow fibre membrane. The coagulation effluent quality and the relative permeability J/J₀ of membrane was determined at the circulated floc dosage of 22, 44 and 66mg/l. The experiment results indicated that the addition of circulated floc obviously improved the flux decline and the degree of improvement was closely related to the dosage of circulated floc. Compared to traditional coagulation, the contact circulated coagulation was an economic and efficient method to retard the membrane fouling.

Abstract: The aim of the research was to investigate the efficiency of fulvic acid or straw water as an alternate amendment to chelating agents, to enhance the uptake of arsenic from groundwater by Vetiveria zizanioides. Fulvic acid and straw water were applied separately to arsenic-contaminated groundwater at different concentrations (0.1% and 0.01%). It was found that when the higher concentration (0.1%) of straw water was added to the groundwater solution, the efficiency of arsenic accumulation by roots was increased by 47.8%. Straw water not only enhanced the growth of Vetiveria zizanioides but also improved arsenic accumulation in both the shoots and roots. In contrast, the addition of fulvic acid (at high or low concentrations) resulted in the reduction of the growth Vetiveria zizanioides. Specifically, a high concentration (0.1%) of fulvic acid reduced arsenic accumulation in the roots whilst a low concentration (0.01%) of fulvic acid decreased arsenic accumulation in shoots.

Abstract: In this study, the removal of phosphorus from wastewater was performed using electro-coagulation by Aluminum electrode. Several parameters was investigated such effect of pH (1.5;3;5;9;11) ,effect of initial concentration (5mg/l ;10mg/l) and concentration of COD (300-800 mg/l). Removal of phosphorus without optimization of the parameters is 77 %. Optimization of the parameters for removal of phosphorus shows, effect of initial pH, initial concentration of phosphate and COD are 93 % , 93 % and 90.3% to 55min with 0.8 A, respectively. This proves a great optimization of phosphorus removal.

Abstract: The degradation of Rhodamine B, a common pollutant existing in industrial wastewater, has been explored using a hydrodynamic cavitation reactor combined with CCl₄ treatment. The effects of CCl₄ concentration, operating pH values, inlet pressure, initial temperatures and initial RhB concentration were investigated. The result shows that the removal of RhB increases from 70.78% to 80.38% with increasing CCl₄ concentrations during hydrodynamic cavitation. Degradation of RhB with CCl₄ treatment increased as the operating pH value and its initial concentration decreased, a 7-fold increase (from 0.22×10² min¹ to 1.68×10² min¹) in the kinetic rate constants were found at pH values ranging from 4.0 to 2.0. In addition, RhB degradation with CCl₄ treatment increased as the inlet pressure and temperature increased. From the present work, we conclude that the RhB degradation reaction follows a pseudo-first-order kinetics, and the mechanisms of CCl₄ enhancement are subsequently discussed.

Abstract: A series of batch mesophilic anaerobic digesntion were conducted using an automatic methane potential test system (AMPTS) and the kinetics of methane production was also discussed using modified Gompertz equation, Logistic function, First-order kinetics model and Transference function, respectively. The results showed that the kitchen waste solid residual was of high biomethane potential, and the maximum specific methane yield was obtained 585 NmL/g TS at inoculums substrate ratio (ISR) 2:1. All of the four models could appropriately fit the accumulative methane production in steady state (R²>0.95), where the 1^st-ordre model and Transference function were relatively much better (R²>0.99) than the other two models. The maximum methane production and maximum methane production rate obtained from the Transference function were 569.32 NmL/g TS and 150.22 NmL/g TS day; the maximum kinetics constant obtained from the 1^st-order model was 0.272/day; the lag time (λ) was basically negligible in all the cases. These parameters were quite close to the experimental results.

Abstract: Aiming at the toxicity effect of trivalent chromic ions on activated sludge in SBR process system, by determination of the settling volume SV, the effects of trivalent chromic ions on sludge settling volume SV in the settling period of SBR process was studied. The results show that trivalent chromic ions will make the sludge volume increase under low chromium load. Moreover, the sludge volume will increase with increasing chromium load, but the settling volume of the activated sludge at 30 min begins to increase in waves as chromium load continues to increase. When the chromium load increases to a certain level, the settling volume of the activated sludge at 30 min continues to decline in waves and is finally lower than the sludge settling volume of the contrast system at 30 min. The experiment suggests that trivalent chromic ions have toxicity and flocculation effects to the activated sludge, and the interaction of the two effects leads to the change of the activated sludge in waves as the chromium load increases.

Abstract: Coordinated chitosan-Cu²⁺ as a carrier, the laccase was immobilized on it by polymeric coordination method. In this study, the optimal conditions for immobilization and properties of laccase were investigated. The optimal conditions for immobilization were: CuSO₄ (0.05 mol/L), complex time (7 h), laccase concentration (250 U/mL), immobilization time (8 h). Under this condition, the activity of immobilized laccase can reach 820 U/g. In comparison with the free laccase, the optimum pH and temperature of immobilized laccase have a little change, while the heat resistance and pH stability were improved. After the immobilized laccase was stored in the refrigerator at 4 °C for 25 days, the activity of it remained 69.5 % of the original, it illustrates the immobilized laccase has a good storage stability. The laccase immobilized with chitosan-Cu²⁺ has high activity and has potential to use in industry as a biocatalyst.

Abstract: Substrate clogging in subsurface wastewater infiltration system (SWIS) is a significant problem that affects hydraulic capacity and operational performance. The mechanisms for substrate clogging were reviewed. The factors affecting substrate clogging were discussed as well. The strategy to ease and prevent substrate clogging phenomena was put forward.