Papers by Keyword: Removal

Abstract: In this work the adsorption of phosphate using the Fe-Cu bimetal oxide modified fly ash was studied. The experimental results showed that phosphate could be effectively removed in the pH range between 4 and 10. The removal percentage of phosphate reached maximum at pH 6.0. The adsorption of phosphate by the modified fly ash was rapid, and the adsorption percentage of phosphate could reach 91.20% in 5 minutes. The removal efficiency of phosphate increased with the increase of adsorbent dosage and the decrease of the initial concentration. The adsorption of phosphate could be described well by Langmuir isotherm, the Langmuir constant Q₀ was 26.03mg/g.

Abstract: Green manufacturing is important subject. In order to reduce waste disposal cost and environmental load, decreasing machining fluid that contains several chemicals such as oil, extreme pressure agent etc. is demanded. In this investigation, the electric rust preventive machining method system that uses only water as machining fluid have been developed. This paper mentioned about evaluation of recycled water quality. The refined water that is purified with developed water recycle system which is installed reverse osmosis membrane (RO) is too clean to evaluate by normal method till now. Using laser turbidity meter, precise water purification is evaluated precisely. Therefore, it is clarified that RO refined water turbidity (RO1=0.0006, RO2=0.0003) is very low compared with clean tap water (0.1207). So, water recycle system can remove contaminating fine particle from water. It is expected that scratch less ultra precision machining with water is enabled to conduct with high filtration ability.

Abstract: Tungsten based products are extensively used in engineering practices. However, there exist some controversies in deformation behaviour between polycrystalline tungsten and its bulk counterpart. In this work, elastic modulus, hardness and removal characteristics of polycrystalline tungsten (poly-W) were investigated by use of nanoindentation and nanoscratch. Atomic Force microscopy (AFM) and Scanning Electron Microscopy (SEM) were employed to characterize the surfaces prior to and after indenting/scratching. The elastic modulus and hardness of the poly-W obtained were 323.6 and 7.1 GPa, respectively. Elastic recovery was barely observed in poly-W after indenting and scratching, indicating that the material was dominantly deformed in plastic regime. The plastic deformation of the poly-W was found to be somehow different from the bulk W, but similar to that of single crystal W nanowhiskers. In multi-scratch test, the pitch distance and scratching speed demonstrated to affect the roughness of the scratched surfaces.

Abstract: t is challenging to achieve good surface quality and high efficiency simultaneously when machining thin film solar panels. In this study the machining characteristics of a multilayered thin film structure were investigated using diamond wire sawing and grinding. It was found that the efficiency in sawing was significantly greater than that of the employed grinding process, but the machined surface quality was much worse. The results indicated that grinding could still be the solution for such processing and sawing must be improved before this technology could be further progressed for machining thin film multilayered structures.

Abstract: The montmorillonite supported nanozero-valent iron material (MT-NZVI) was synthesized to remove cadmium (Cd). The results showed that the removal efficiency of MT-NZVI on cadmium was much higher than that of montmorillonite (MT), and the removal efficiency of MT-NZVI on cadmium reduced with the increase of the initial concentration and the pH value, but increased with the increase of the dosage.

Abstract: The adsorption of freshwater fish scales were used to remove Hg²⁺ in industrial wastewater. The effects of pH, shaking time, initial concentration on the adsorption Hg²⁺ onto freshwater fish scale were investigated. In these conditions, by varying the pH of the mercury (II) solutions from 2 to 8, the removal efficiency remained higher than 96%. Optimal adsorption capacity was 117.2 mg g^-1 at pH 6.0. Characterization of the biosorbent fish scales was performed using scanning electron microscope (SEM), and Fourier transform-infrared (FTIR) spectroscopy. The mechanism for the adsorption was studied. The adsorption of Hg²⁺on to freshwater fish scale could be described by Langmuir isotherm model.

Abstract: The use of low-cost and eco-friendly adsorbents has been investigated as an ideal alternative to the currentexpensive methods of removing arsenic from wastewater. Orange peel was collected from the local fields of orangetrees and converted into a low-cost adsorbent. The effects of solution pH, contact time, and concentration of orange peel have beenstudied. The maximum adsorption capacity calculated from the Langmuirisotherm model was 43.69 mg g^-1,Based on the adsorption capacity, the pretreating orange peel was shown to be promising materials for adsorption removal ofarsenics from aqueous solutions.

Abstract: The present study deals with comparative evaluation of three different aquatic macrophytes, i.e. Myriophyllum spicatum, Sagittaria sagittifolia and Pistia stratiote planted at three different concentrations (1.0, 3.0 and 5.0 mg/L) of metals in laboratory experiment for Cd, Cu and Zn removal from aqueous solution. Result revealed high removal (>90%) of different metals during 15 days experiment. Highest removal was observed on 13th day of experiment, thereafter it decreased. Results revealed Pistia stratiote as the most efficient for the removal of selected heavy metal followed by Sagittaria sagittifolia and Myriophyllum spicatum. Selected plants can be used for large scale removal of Cd, Cu and Zn from waste water.

Abstract: Heavy metal pollution of water is of concern for human health and ecosystem. Under present investigation Pistia stratiotes L. (water lettuce) has been tested for removal of two important heavy metals chromium (Cr) and lead (Pb) from metal solution. This species was grown at four concentrations of Cr and Pb, i.e. 5.0, 10.0, 15.0 and 20.0 mg/L, respectively in single metal solution. This aquatic macrophyte has successfully removed up to 80% of Cr and 93% of Pb after 10 days. The bioconcentration factor (BCF) value ranged between 299 and 1026 for Cr and between 1672 and 1852 for Pb, respectively. The amount of BCF in Pistia stratiotes showed that removal of Pb was higher than removal of Cr. The accumulation of heavy metals was more obvious in the roots as compared to leaves. These findings contribute to the application of aquatic macrophytes to lead and chromium removal from moderately contaminated waters.

Abstract: An effective adsorbent for the removal of arsenate from aqueous system was synthesized by loading ferrihydrite on attapulgite (ATP). The effects of various parameters such as heat modified temperature and particle size of ATP, Fe (III) concentrations, adsorbent dosage, solution pH on the removal rate of arsenate were assessed. The results showed that 600 °C modified ATP loaded with Fe (III) sorbent had better arsenate removal efficiency than 200 °C and 400 °C modified ATP. The removal efficiency of As (V) increased significantly with decreasing the particle size of ATP. Arsenate was effectively adsorbed by ATP loaded with Fe (III) sorbent in the pH range of 57. Equilibrium data of arsenic adsorption fitted perfect with Langmuir isotherm model. The removal rate of As (V) by ATP loaded with Fe (III) sorbent was 95.8% at the optimal conditions from drinking water. The results showed that ATP loaded with Fe (III) sorbent can be used for the arsenate removal from aqueous system.