Advanced Materials Research Vols. 550-553

Abstract: With anaerobic granular sludge as adsorbent, the adsorption kinetics and thermodynamics of methylene blue (MB) from aqueous solution was studied by batch adsorption technique.The pseudo-first order, pseudo- second order models and Langmuir, Freundlich isotherms models were used to describe the kinetic data.The experimental results show that the anaerobic granular sludge had strong and fast speed adsorption capacity for MB adsorption in wastewater. The adsorption equilibrium could be reached in 2h, and the maximum adsorption rate was 98.6%. the pseudo-second order equation is the best model that describes the adsorption behavior.The equilibrium data were fitted to Langmuir isotherms and the equilibrium adsorption was well described by the Langmuir isotherm model. The calculation values of thermodynamic parameters present that the adsorption is spontaneous and endothermic in nature.Our results suggest the anaerobic granular sludge is a potential MB cleaner in wastewater.

Abstract: A aerobic bacterium strain P2 isolated from coking wastewater, was able to utilize phenol, o-cresol and pyridine as its sole carbon and energy source. The morphological properties and the phylogenetic analysis based on 16S rDNA sequences showed strain P2 belonged to the genus Diaphorobacter sp.. The optimum biodegradation of phenol was 37°C, pH 7.0-9.0 and 0.25% NaCl , respectively. The growth arrearage period was prolonged with the phenol concentration. The growth of Diaphorobacter P2 and phenol-degradation were inhibited completely by 50 μmol/L metal ions, such as Cu^{2 +}, Ni²⁺, Cd²⁺ or Cr⁶⁺. Orthogonal experiment indicated the order of metal toxicity to biodegradation of P2 was Zn²⁺>Mn²⁺>Pb²⁺ under various heavy-metal compounds. The phenol biodegradation in coking wastewater supplemented with 2/3 beef extract peptone medium was degraded fully in 3 days, indicating that nutrient solution was beneficial for P2 growth and phenol degradation in wastewater. Those results suggest that the Diaphorobacter P2 has potential for treatment of coking wastewater.

Abstract: The present paper is aimed to investigate and develop renewable adsorption methods for four dyes removal from wastewater using pore-expanding mesoporous material. The sorption kinetics, sorption thermodynamic and the renewable adsorption test were evaluated. The adsorption process attained equilibrium within 60min, which show that the adsorbent can remove of the dye in a short time. It was shown that the process best described by the pseudo-second-order equation. Various thermodynamic activation parameters such as enthalpy of sorption △H, Gibbs energy change △G and entropy △S were estimated. The negative values of △G indicate that adsorption of dye with the adsorbent was spontaneous, while positive △H values indicative of endothermic nature of the adsorption. The negative △S values for the adsorbents show decreased randomness at the solid solution interface during the adsorption of dye. The adsorbent, washed by NaOH, can be reused by regeneration decolorizing process.

Abstract: Electrocoagulation is an electrochemical technique for treating polluted effluent, such as dye wastewater. In this paper, Remazol Brilliant Blue R was decolorized by electrocoagulation method used iron electrode. The operating cost was also considered to confirm the optimum operation conditions. High decolorization efficiency (>99%) for Remazol Brilliant Blue R dye solution was obtained with 15mA cm-2 of current density, 10min of electrolysis time, pH 6 and 500mg l-1 dye concentration.

Abstract: A membrane-aerated bioreactor (MABR) was developed for the wastewater treatment with simulated oilfield wastewater. Long-running experimental results showed that the removal percentages of oil and COD were 80-90% and 75-85% respectively and the concentration of NH4+-N was less than 2 mg/L, turbidity less than 50 NTU in the effluent. The results lay a good foundation for further research and development of MABR treatment process and technology. MABR has the technical feasibility for the oilfield wastewater treatment.

Abstract: The effects of sewage sludge on combustion of loading alkali metal pulverized coal is carried out by thermogravimetric analysis (TGA). The result shows sewage sludge decreases initial release temperature and ignition temperature of volatile matter(VM) during the combustion of loading alkali metal pulverized coal. The combustion of fixed carbon in coal was promoted by the metal material in sludge when the sludge mixing ratio(SMA) was lower than 20% or inhibited because of the cover of sludge ash when SMA was higher than 40%. Comparison of stacking curves of sludge and measured curves of loading alkali metal coal, finds that: (1) there is no effect between sludge and coal, for the volatilization of water and small molecule substance, the combustion characteristic curves are superimposed in both experimental curves; (2) the co-combustion is interactional and interrestricted continuous change process, can't direct obtain from superimposition of curves, for the combustion of VM and fixed carbon. While SMA is lower than 20%, the samples have good combustion characteristic than pure coal.

Abstract: With the development of economy and electronic technology, Lithium-ion Batteries（LIBs）have become new flourishing energy-materials. With the wide utilization and consumption of them, there are large amounts of spent lithium-ion batteries produced. The LIBs contain many valued metals, and the recovery and utilization of them can not only reduce environmental pollution, but also slow the lack of resource effectively, increase social and economic benefit. These methods for recovery and separation of LIBs are introduced, and the existing problems and prospect of the recycling recovery technologies are put forward．

Abstract: COD from heavy oil wastewater was removed by activated carbon on room temperature. It was showed that removal efficiency of COD reached above 65% under the condition of 50min of adsorption time, 7 of pH, 6g of the used activated carbon and 1kg of activated carbon was used to treat 1m3 of heavy oil waste water.

Abstract: A pilot-scale modified SBR process was used to treat urban wastewater. The average NH₄⁺-N efficiency removal was 98 %. The average TN removal efficiency was 52 %. The average TP removal efficiency was 85 %. The average COD removal efficiency was 85 %. The average effluent NH₄⁺-N was 0.34 mg/L. The average effluent TN was 12 mg/L. The average effluent phosphorus was 0.75 mg/L. The average effluent COD was 35 mg/L. The result shows that the increase of 100 mg/L MLSS concentrations by proliferation or decrease of 100 mg/L MLSS concentrations by discharging residual sludge can remove 1 mg/L total phosphorus from wastewater. The faster the MLSS increases, the higher efficiency the phosphorus removal is achieved. When MLSS is fluctuating or decreasing, the phosphorus removal would be worse than MLSS increase. When MLSS increases 500 mg/L everyday, phosphorus removal efficiency would be very high; the average phosphorus removal efficiency would be higher than 90 % in the most urban wastewater treatment plant.

Abstract: The adsorption of hexavalent chromium [Cr(VI)] from aqueous solutions using weakly basic ion-exchange resin D301 was studied in this work. The result showed that the adsorption of Cr(VI) was strongly dependent on pH, the optimum condition was investigated at pH 2 and the maximum adsorption capacity was 247.71 mg g^-1. The equilibrium datas were fitted well with Langmuir and Redlich–Peterson isotherm models. The pseudo-second-order rate equation was best represented by the adsorption process.