Papers by Keyword: Removal

Abstract: The purpose of the present study was to investigate the ability of Microbacterium liquefaciens strain MNSH2-PHGII-2, isolated from a Mexican silver mine, for removing Ni and V from spent catalyst at 80% (w/v) pulp density in a glass-column system at laboratory conditions. Firstly, microbial culture was adapted to spent catalyst at 0.1% (w/v) in liquid culture then, it was assayed by its ability to remove Ni and V from a spent catalyst in a glass-column system. Spent catalyst was packed at 80% (w/v) pulp density and inoculated at 20% (3x10⁸ CFU/ml); air was supplied at 80 ml/min and then incubated at 30°C during 14 days. Parameters such as microbial growth, pH, Ni and V residual concentrations, in catalyst, were determined at days 7 and 14. The result showed that Microbacterium liquefaciens strain MNSH2-PHGII-2 in the glass-column system was able to remove 1007.4 mg/kg of Ni while V was removed at an extent of 5360.5 mg/kg. Microbial removal for other metals in catalyst was non-significant, that indicated the specificity of Microbacterium liquefaciens to remove Ni and V.

Abstract: Landfill leachate generation is one of the main problems from sanitary landfill. Chemical oxygen demand (COD), ammoniacal nitrogen (NH₃-N), and color are among the most problematic parameters in stabilized leachate. In this regard, dedicated treatment facilities are required before leachate can be discharged into the environment. The performance of the combined ozonation (O₃) and zirconium tetrachloride (ZrCl₄) to treat two types of stabilized leachate was investigated during this study. Leachate samples were collected from an anaerobic stabilized leachate (Alor Pongsu Landfill Site, APLS) and semi-aerobic stabilized leachate (Pulau Burung Landfill Site, PBLS). Zirconium tetrachloride dosage was determined as 1 g/1 g (COD/ZrCl₄ ratio) and then added to the leachate samples with 60 min ozonation at natural leachate pH (8). COD, color, and NH₃-N were removed from the APLS sample at 33%, 70%, and 53% rates, respectively, whereas 48%, 75%, and 69%, respectively, from the PBLS samples. Ozone consumption was also calculated with the highest value (3.81 Kg O₃/ Kg COD) reported in PBLS, whereas the lowest value (2.32 Kg O₃/ Kg COD) was reported in APLS. Biodegradability of (BOD₅/COD) was investigated and improved from 0.07 to 0.08 for the APLS samples and 0.05 to 0.11 for the PBLS samples after leachate oxidation. Results showed that the performance of O3/ZrCl₄ oxidation is more efficient in treating semi-aerobic stabilized leachate than anaerobic stabilized leachate Moreover, the combined method proved to be more efficient in remediating leachate compared with ozone and zirconium treatment alone.

Abstract: It was hard to make a thinner film of hydrogen permeable alloy by rolling when small nonmetallic inclusion particles with the size of 5 to 30 μm were present in the alloy. For this reason, the removal of nonmetallic inclusion particles from Pd-Gd alloy were examined using various fluoride fluxes. In the experiments on the removal of nonmetallic inclusion particles from Pd-7 to 16 mass% Gd alloys, the lowest total oxygen content was obtained by the addition of GdF₃ flux.

Abstract: A microwave-induced catalytic removal device was designed and set up for studying removal of hazardous or toxic gas from contaminated air. Catalytic oxidative Removal ratios of several hazardous gases of VOCs, CO and H₂ under microwave field were tested. Results suggested that structure of hazardous gas and catalyst type were main factors affecting the removal efficiency of hazardous gas. Oxidative catalyst contributed to removal of reductive gas. In addition, the flow rate also affected the removal efficiency.

Abstract: In the paper, the optimization of the coagulation process for Kaolin and humic acid removal using polymeric aluminum ferric sulfate (PAFS) was studied. In order to obtain the maximum turbidity and humic acid removal efficiency of Kaolin and humic acid simulated wastewater, the optimum coagulation conditions was investigated with the factors of mixing speed and time. Furthermore, mixing speed and time including parameters affecting the coagulation performance such as rapid mixing speed, rapid mixing time, slow mixing speed and slow mixing time using single factor and orthogonal array L9 (34) analysis were examined. The results showed that the optimum single factor of mixing speed and time indicated rapid mixing speed of 350 rpm, rapid mixing time of 1.0 min, slow mixing speed of 60 rpm and slow mixing time of 20 min. Then the orthogonal optimization experiment of mixing speed and time indicated maximum HA removal efficiency was 97.5% at rapid mixing speed of 350 rpm, rapid mixing time of 1.25 min, slow mixing speed of 60 rpm, and slow mixing time of 20 min.

Abstract: This study was performed to determine the feasibility of enhancing removal of zinc ions from aqueous solutions using an iron-carbon internal micro-electrolysis (ICIME) followed by iron hydroxide self-flocculation (IHSF) process. Results shown that the Zn²⁺ removal using ICIME was improved by IHSF significantly. The pH=3, mass ratio of Fe/AC=2: 1, hydraulic reaction time=30min of ICIME and pH=9, both aeration time and static placing time were 60min of IHSF were proposed as the optimum conditions. Under these conditions, the removal efficiency and residual concentration of Zn²⁺ from lead and zinc smelting wastewater were reached 99.10%, 1.32mg/L. Meanwhile, other metal ions and the F^- also were removed effectively. Lead and zinc smelting wastewater could meet the discharging standard (integrated wastewater discharge standard (GB8978-1996)) of China. The Zn²⁺ removal was significantly influenced by other metal ions existing in aqueous solutions. Contrast and breakthrough time experiment indicated the Compare with single Fe and ICIME, ICIME followed by IHSF have a higher efficiency and bearing capacity for Zn²⁺ removal. ICIME removal of Zn²⁺ enhanced by IHSF is a feasible method.

Abstract: A novel organic-inorganic PAA@Fe-Si composite material was synthesized by acrylic acid and mesoporous iron-incorporated material and used as an efficient and specific adsorbent for the removal of methylene blue (MB), a cationic dye from aqueous solution. The properties of the composite material were characterized by scanning electron microscopy, Fourier transform infrared and thermogravimetric. The effects of initial solution pH, adsorbent dosage, and contact time on MB adsorption and temperature have been investigated. The results showed that the maximum adsorption capacity of PAA@Fe-Si reached 587mg/g at 298 K, which was much better than pure Fe-Si adsorbent.

Abstract: This study aimed to investigate the effect of grinding conditions, including depth of cut and grinding direction, on the material removal and surface finish of multilayered thin film structures. It was found that the increase in depth of cut improved the material removal rate, but worsened the ground surface finish. The grinding perpendicular to the thin films caused less damage and produced better surface than that parallel to the films. The characteristics of wheel wear were also studied. Grit pull-out and micro-fracture should be attributed to the wheel wear.

Abstract: The deformation and removal mechanism of a multilayered thin film structure involved in nanoscratching and diamond lapping processes were investigated. The results obtained from the two processes were compared, in terms of deformation characteristics and surface finish. It was found that both nanoscratching and lapping demonstrated similar characteristics. This work provides insight into the deformation and removal of a thin film multilayered structure under mechanical loading, and thus the outcome is of value for developing the efficient machining process for such structures.

Abstract: Ditch pond wetland systems have the capacity to remove and purify non-point pollutants of nitrogen and phosphorus from agricultural drainage. This paper measured the changes of nitrogen and phosphorus content in ditches, ponds of runoff water, aquatic plants and sediment. The results show that ditch, pond has the very good intercept and removing effect for nitrogen and phosphorus. The total removal rate of TN and TP were 61.13% and 63.08% in ditch pond wetlands. Phragmites communis, Zizania latifolia, reed nitrogen absorption per unit area respectively were 2.468 g/m², 1.795 g/m², 2.174 g/m². Phragmites communis, Zizania latifolia, reed absorb phosphorus amount per unit area respectively were 0.643 g/m², 0.351 g/m², 0.338 g/m². The TN content and TP content of sediment is increase from ditches1to ditches3. TN content of sediment at pond import is higher than at pond export. TP content changed little in the pond sediment.