Papers by Keyword: Removal

Abstract: Spherical sponge iron (SSI) with high activity and intension could be prepared through direct reduction by hydrogen. pH value in solution increased despite initial pH because a large amount of H⁺ was depleted along with erosion battery reaction of SSI. It was suggested that initial pH has significant influence on pH value in solution and cadmium removal percentage by SSI. When the initial pH maintained at 2.03, cadmium removal percentages were only 10.17% and 22.00%, respectively, in 10min and 30min. While the initial pH was adjusted to 3.00, cadmium removal percentage could be elevated to 73.10% and 95.46% in similar libration time. Cadmium removal by SSI appeared to be the first-order reaction. When the initial pH was maintained at 2.03, the apparent reaction rate constant of cadmium removal by SSI was only 0.434 and 1.027 h^-1, while which could be elevated to 5.882 and 5.249 h^-1 when the initial pH was adjusted to 3.00.

Abstract: The important step for increasing gaseous elemental mercury (Hg⁰) removal in wet scrubber systems is altering the chemical form of the Hg⁰ to a water-soluble oxidized species. This work focuses on the removal of elemental mercury from simulated flue gas by aqueous K₂S₂O₈ in a bubble reactor. In the system of K₂S₂O₈ oxidize Hg⁰, the reaction velocity of K₂S₂O₈ and Hg⁰ is soon. Reached a higher removal rate after 10min. Increase the concentration of K₂S₂O₈ can remarkably improve the removal rate of Hg⁰to 85% With the rise of import mercury concentration has increased mercury removal rate to 89.5%.

Abstract: The performance of native eggshell membrane in removing of malachite green (MG) from aqueous solution was investigate. The effect of pH, adsorbent concentration, temperature, and contact time were performed by static testing. The maximum biosorption was both observed at pH 6.0 on the eggshell membrane. Optimal adsorption capacity (89.72 mg g-1) at initial concentration 100 mg L-1 and rate (98.69%) was obtained at pH 5.5. Characterization of the biosorbent eggshell membrane was performed using scanning electron microscope (SEM), and Fourier transform-infrared (FTIR) spectroscopy. The kinetic and equilibrium studies suggest that the adsorption follows Langmuir isotherm model. Desorption studies revealed that MG could be well removed from wastewater.

Abstract: The occurrence and removal of selected pharmaceuticals have been investigated in a municipal wastewater treatment plant (WWTP) of Shanghai in this study. Ibuprofen (IBP), naproxen (NPX), ketoprofen (KEP), diclofenac (DFC), and clofibric acid (CA) were selected as target compounds. Results showed that all of these pharmaceuticals were detected in the influent samples with IBP showing the highest concentrations (1380 ng/L). The partition coefficient (logKd) between the particulate and the dissolved phase calculated for KEP, NPX, CA, DFC, and IBP ranged from 1.2 to 2.2 in the raw sewage and the treated effluent suggesting the weak tendency of the target pharmaceuticals being absorbed onto particles. Different compounds were removed to different extent in the WWTP treatment processes. The highest removal efficiency was observed for IBP and the lowest for CA, 87.2% and 36.7%, respectively. The results indicated that municipal WWTP cannot remove these pharmaceuticals efficiently.

Abstract: Experiments were performed to investigate the As(III) and As(Ⅴ) removal on manganese dioxide. 0.5 grams of manganese dioxide was reacted at room temperature for 3 hours with 50 mL As(III) or As(V) in synthesized groundwater. Throughout the reaction, concentration of arsenic decreased from 1.25 mg/L to 0.70 mg/L in As(Ⅴ) system, arsenic removal was about 44.27%. While in As(III) system, concentration of total arsenic decreased from 1.92 mg/L to 0.85 mg/L, arsenic removal was about 55.85%. When As(III) reacted with manganese dioxide, the concentration of As(Ⅴ) in solution reached the maximum value for the oxidation of As(III) after 45min, afterwards As(Ⅴ) decreased slowly for adsorption on manganese dioxide. In regard to total manganese concentration, it was 1.25 mg/L in As(III) system, was about 1.25 times of that from As(Ⅴ) system, this phenomenon was due to the redox of As(III) with manganese dioxide.

Abstract: This paper reports our recent results on the nanoindentation and nanoscratch of LiTaO3 single crystals. The elastic modulus and hardness of LiTaO3 obtained from nanoindentation were 251±3 GPa and 12.6±0.6 GPa, respectively. During indenting, pop-in events occurred when indentation load was in the range from 305 to 640 μN. Incipient kink bands (IKBs) were believed to be responsible for the pop-ins. Nanoscratching showed that there existed a threshold normal load of 2.5 mN, above which cracks were generated and the material removal was in the brittle regime. The knowledge gained is valuable to the design of an effective machining process for LiTaO3 crystals.

Abstract: This paper summarised our recent results on the development of grinding technologies for the fabrication of aspheric components at micro/meso scales made of cemented tungsten carbide. Based on these results, a grinding protocol was proposed for the fabrication of aspheric moulds. The protocol includes the understanding of deformation and removal mechanisms of hard and brittle materials involved in grinding, the preparation of grinding wheels, the compensation of profiling errors and the optimisation of the grinding process.

Abstract: Sulfhydryl lignin was prepared by immobilizing sulfhydryl onto wood lignin. The effect of pH, temperatμre, adsorption time, salinity of condiment and amino acid concentration of condiment on the adsorption behavior of sulfhydryl lignin was investigated, respectively. The adsorption kinetics and thermodynamics of Cu(Ⅱ) were also studied.

Abstract: Microorganisms were screened from oil wastewater in Daqing Oilfield, by acclimatization, isolation and purification of microorganisms, bacterium as the only nitrogen source was obtained, which was named for strain Y-1. Experiment of identification showed that Y-1 was identified to Bacillus Cereus. Strain Y-1 was used for paraffin removal on three wells: Well Nos. 12-36, 13-39 and 14-43 in Yushulin Zone Daqing Oilfield. The results indicated that the tested wells obtained good effects after microbial treatment: the reduction rate of oil viscosity was 23.6%, the freezing point of crude oil reduced by 2.1°C, the reduction rate of oil surface tension was 38.0%, pH value was reduced from 7.2 to 6.2, daily oil production increased from 1.7t·d^-1 to 2.4t·d^-1, the rate of growth was 41.2%, the period of hot washings prolonged from 40d to 149d and the number of hot washings reduced by 4 times in Well 12-36; the reduction rate of oil viscosity was 24.8%, the freezing point of crude oil reduced by 2.7°C, the reduction rate of oil surface tension was 42.5%, pH value was reduced from 7.2 to 6.8, daily oil production increased from 1.2t·d^-1 to 1.6t·d^-1, the rate of growth was 33.3%, the period of hot washings prolonged from 45d to 158d and the number of hot washings reduced by 5 times in Well 13-39; the reduction rate of oil viscosity was 22.5%, the freezing point of crude oil reduced by 3.2°C, the reduction rate of oil surface tension was 42.5%, pH value was reduced from 7.2 to 6.4, daily oil production increased from 0.8t·d^-1 to 1.1t·d^-1, the rate of growth was 37.5%, the period of hot washings prolonged from 30d to 122d and the number of hot washings reduced by 5 times in Well 14-43. The direct economic income exceeded 210,000 Yuan.

Abstract: In order to further improve the effect on microbe degrading polyacrylamide(HPAM), this paper presented combined process of the microbial degradation of poly-containing wastewater, the innovation of this paper was added to the combination process by immobilized particles, immobilization granules were prepared by the mixed bacterium, simulation experiment on the treatment of poly-containing wastewater was done. Process simulation experiments was divided into components including static and dynamics, biochemical capacity was adjusted by static experiment, wastewater after adjustment was biochemical. After dynamic simulation experiment, the effluent quality indicators tended to be stable after 3d, degradation rate of HPAM was 79.5%, crude oil removal rate was 98.7% and the removal rate of COD_Cr was 86.4%, which attained the National Secondary Emission Standard.