Abstract: In this work, the biodegradation of nonylphenol by Rhodotorula sp. in batch culture was investigated over a wide concentration range (11~160 mg/l). Experimentally nonylphenol was an inhibitory type substrate to Rhodotorula sp.. Five kinetic models (Haldane, Webb, Yano, Aiba, and Teissier) were fit for the experimental growth kinetic data. It was found that the Haldane model was the most suitable one to predict the degradation of nonylphenol. The kinetic analysis demonstrated that bacterial growth and nonylphenol degradation of Rhodotorula sp. were based on a substrate concentration inhibition model. Analysis of growth factors indicated the highest specific growth rate (μ) of 0.127 h-1 was obtained at the initial nonylphenol concentration of 12.76 mg/l.
Abstract: Membrane property decay has great effects on propylene yields when compression/condensation/membrane process is applied to recover propylene monomer. There are four types of membrane property decays. The first case is that selectivity keeping constant but membrane flux decreasing, the second case is that selectivity reducing but membrane flux unchanged, the third case is that selectivity reducing but membrane flux increasing, and the last case is that both of them all decreasing. One purpose of this paper is to judge which kind of decay leads to the separation deterioration according to the change of some parameters in the process by simulation. In order to meet target requirement, two operation parameters, membrane pressure and condensation temperature, are regulated. Results indicate that propylene yields decrease when any type of membrane property decay emerges, and the type of membrane property decay can be distinguished by the change trend of propylene yields, the variation of recycle permeate gas flow as well as propylene concentrations in permeate gas. What’s more, membrane pressure is a prior operation parameter to be regulated so as to counteract the effect of membrane property decay to some extent.
Abstract: Removal rates of Pb, Hg and As ions in lotus leaf extracts obtained by Micelles- complexation-supercritical CO2 extraction through an orthogonal experiment(L16(45)) were investigated to get the best extraction conditions. The results of orthogonal experiments indicated that the removal rate of Pb, Hg and As ions trace heavy metal ions is high by complexaction and reverse micelles in supercritical carbon dioxide (Sc-CO2), and the removal rate of Pb, Hg, As from lotus leaf is 87.85%, 89.19% and 84.72% respectively with the loss rate of total flavonoids is 8.73% under the potential optimum conditions which are 50°C, 20 MPa, 1.5 h, the concentration of Triton X-100 of 0.15 mol.L-1, the mass of complexing agent is 0.1 g.
Abstract: The photocatalytic reduction of CO2 could be achieved over Cu/S-TiO2 under UV and visible light irradiation. S-TiO2 was fabricated via calcination of TiO2 precursor and thiourea, Cu species were plated on the surface of S-TiO2 by electroless plating method. XRD revealed that S-TiO2 was anatase phase, UV-Vis absorption spectrum showed an excellent visible light absorption of Cu/S-TiO2. Cu species plated on S-TiO2 by electroless plating method could facilitate the photogenerated charges capture, separation and transfer. The products of CO2 photocatalytic reduction involved gas phase of methane, carbon monoxide and hydrogen, and liquid phase of methanol, formic acid and acetic acid. The in-situ IR spectra indicated that the OH radical acted as an intermediate participating in the photocatalytic reaction.
Abstract: Novel floatation collector for phosphate ore, α-chloro oleic acid monoester of tartaric acid, was synthesized by steps of chlorination, acylation, esterification with oleic acid as raw material. The flotation properties for a low-grade collophanite in Hubei were evaluated. Result showed that novel collector had better performance than common fatty acid collector by less dosage. Its further application and promotion is significant for reducing the mineral processing cost of low-grade phosphate rocks.
Abstract: The influences of HRT, C/N ratio on simultaneous nitrification and denitrification (SND) and the rule of pH in a sequencing batch reactor (SBR) were investigated while treating low C/N synthetic municipal wastewater. The results showed that the function of SND became more outstanding and the removal rate of TN, NH4+-N was improved greatly by lengthening HRT appropriately; when the C/N increased, the denitrification effect of the simultaneous nitrification and denitrification would be improved; .At the same time, the variation of pH value was well related to ammonia oxidation. So that judgment on the ending of nitrification and denitrification could be based on the inflection point on the varied curve of pH, and thus reducing aeration and mixing time for the purpose of energy saving.
Abstract: A effective and cheap adsorbent, chitosan modified bentonite was prepared in this work. XRD, SEM and FTIR were used to characterize unmodified and chitosan modified bentonite materials. The adsorption property of bentonite and modified bentonite for mythlene blue in wastewater were investigated by spectrophotometry. The effects of initial pH value, sorbent dosage and contact time on the adsorption capacity have been investigated. The chitoan modified bentonite showed excellent removal capacities for methylene blue from waste water.
Abstract: Rhamnolipid (RL) was used to study the removing of polychlorinated biphenyls (PCBs) from contaminated soils. The results showed that RL obviously enhanced desorption of PCBs from soils and RL was more effective than POE(6). Pseudomonas strain LB400 was able to grow rapidly in the medium with RL, POE(6) or biphenyl as carbon source. PCBs biodegraded in growing cells were greater than that in resting cells. In growing cells with RL as carbon source, when the incubating time reached 72 h, PCBs Biodegraded was 98.7% and increased by 0.5% compared with that with biphenyl as carbon source. PCBs degraded were the lowest in all kinds of cell systems with POE(6) as carbon source. In the growing cell system, P.LB400 was able to fully utilize RL, so the cell density and PCBs Biodegraded rapidly increased with the increase of the concentration of RL. However, in the resting cell system, RL had negative impact on biodegradation of PCBs.
Abstract: In order to get the optimum technological conditions of the hydrogen peroxide /sulfuric acid system,the static corrosion method was used to study the related parameters including compositions of the microetching system and the operation temperature. The results of the experiment show that the microetching performance of the hydrogen peroxide /sulfuric acid system was excellent under optimum conditions of maintaining temperature at 30~35, copper concentration about 25 g/L, hydrogen peroxide 30~40 g/L and sulfuric acid content 70~90 g/L . The process of microetching is stable and controllable.
Abstract: A synergistic combination of electrocoagulation and electrooxidation was introduced for the treatment of CTMP wastewater in which most of the colloids and charged species had been removed by electrocoagulatio, then small organics could be mineralized by electrooxidation effectively.The mainly influencing factors for electrocoagulation such as electrolyte, sodium chloride dosage, voltage intensity, current intensity and reaction time were assessed. The optimum conditions were obtained, and the results showed that sodium chloride dosage of 1g/L, voltage intensity of 7.5V, current intensity of 0.6A, 60 min reaction time, its color removal rate was above 90% and CODCr removal rate was about 40%. After electrocoagulation the electrooxidation could further reduce CODCr above 80%.