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Go to Editorial ManagerIn the present work, the agricultural wastes which are wheat bran and raw okra waste used as adsorbent material for adsorption of cadmium and copper ions from wastewater .The effect of adsorption variable which include initial pH of solution , agitation speed, agitation time, initial concentration of cadmium and copper ions, and amount of adsorbent material were investigated in a batch process in order to obtain the maximum ions removal from wastewater .The results obtained from experimental investigation show that the percentage removal of metal ions increases with increasing pH and agitation speed until a maximize value after that it decreased with increasing pH and agitation speed. Also increases with increasing amount of adsorbent material and agitation time until a maximize value then reach a constant value approximately , and decreasing with increasing metal ions concentration .The maximum removal percent of cadmium and copper ions were 85.8% and 52.7 % respectively which obtained at pH equal 5.0, agitation speed 150 revolution per minute, agitation time 105 minute , metal ion concentration 40mg /L ,and adsorbent amount 1.5gm when using wheat bran as adsorbent material ,while obtained the maximum removal percent of cadmium and copper ions were 81.7% and 47.8 % which obtained at pH equal 6.0, and pH equal 5.0 respectively , agitation speed 150 revolution per minute, agitation time 90 minute ,metal ion concentration 40 mg /L ,and adsorbent amount 1.5gm when using okra waste as adsorbent material. From above result the wheat bran and okra waste was a best adsorbent material for removal cadmium and copper ions from wastewater but wheat bran slightly more effective than okra waste._x000D_
The control of quenching process has been investigated in this study by developing a quench system design to simulate the quenching process and measure the time – temperature history inside the sample during the cooling stage. The main purpose of this quench system is to evaluate the quench power of different quenchant at different conditions (type, temperature and agitation).A stainless steel sample was used with a suitable measurement as a probe in designing this quench system.The performance of two of quenchants (water and brine) with different conditions was investigated, and the designed probe was used to illustrate the effect of quenching parameters (quenchant type, temperature and its agitation) on cooling curves and cooling rate.The quenching system has proven its ability to work effectively and the results showed that heat transfer properties were significantly affected by quenchant parameters.
In this study, low cost biosorbent ? inactive biomass (IB) granules (dp=0.433mm) taken from drying beds of Al-Rustomia Wastewater Treatment Plant, Baghdad-Iraq were used for investigating the optimum conditions of Pb(II), Cu(II), and Ni(II) biosorption from aqueous solutions. Various physico-chemical parameters such as initial metal ion concentration (50 to 200 mg/l), equilibrium time (0-180 min), pH (2-9), agitation speed (50-200 rpm), particles size (0.433 mm), and adsorbent dosage (0.05-1 g/100 ml) were studied. Six mathematical models describing the biosorption equilibrium and isotherm constants were tested to find the maximum uptake capacities: Langmuir, Freundlich, Redlich–Peterson, Sips, Khan, and Toth models. The best fit to the Pb(II) and Ni(II) biosorption results was obtained by Langmuir model with maximum uptake capacities of 52.76 and 36.97 mg/g for these two ions respectively. While for Cu(II) the corresponding value was 38.07 mg/g obtained with Khan model. The kinetic study demonstrated that the optimum agitation speed was 400 rpm, at which the best removal efficiency and/or minimum surface mass transfer resistance (MSMTR) was achieved. A pseudo-second-order rate kinetic model gave the best fit to the experimental data (R2=0.99), resulting in mass transfer coefficient values of 42.84× , 1.57× , and 2.85× m/s for Pb(II), Cu(II), and Ni(II) respectively. The thermodynamic study showed that the biosorption process was spontaneous and exothermic in nature.
The electrodes material plays an important role in the amount of electricity produced in microbial fuel cells (MFCs). Metal electrodes used in MFCs are subject to biological and concentration cell corrosion which leads to a decrease in the cell efficiency. In the present work, the corrosion behavior of three selected electrode materials, namely, stainless steel, copper, and zinc under different operating conditions was investigated and discussed. In anode chamber, the microorganism (MO) used was Saccharomyces cerevisiae (yeast) with sodium acetate as a substrate forming the microbial corrosive solution. In the cathode chamber, the corrosive solution is aerated water. The effects of different operating parameters on the corrosion rate (CR) of these electrodes were studied such as: microorganism concentration, aeration of cathode chamber, and flow velocity in cathode chamber. The potential of the each electrode was measured to understand the corrosion behavior of electrodes and the produced current was also investigated. It was found that the corrosion rate of the electrodes in both anode and cathode chambers increases with increasing MO concentration in anode chamber and with increasing agitation speed in cathode chamber. The bio-corrosion is an important part of the corrosion occurring in microorganism chamber. The stainless steel exhibited the lowest corrosion rate for the whole investigated range of operating parameters followed by copper. The zinc electrode was found to be poor as an electrode in MFC as its corrosion rate was very high in all conditions investigated. In addition, this study showed that the air pumping in water chamber causes an appreciable increase in the corrosion rate in both chambers and an increase in the produced current.
Galvanic corrosion of Nickel-Chrome alloy (Ni-Cr alloy) and Copper (Cu) coupled in 5% sulfuric acid solution was investigated. The effects of agitation velocity, temperature, and time on the galvanic corrosion current and the weight loss of both metals in both free corrosion and galvanic corrosion were investigated. The trends of open circuit potential (OCP) of each metal and galvanic potential (Eg) of the couple were also determined. The results showed that Cu was cathodic relative to Ni-Cr alloy in galvanic couple and the corrosion potential of the couple (Ni- Cr alloy /Cu) was between the values of the two single components because the OCP of copper shifted to positive with the increase in velocity. Under stagnant conditions initially the galvanic current was more negative then shifted to the positive with time. The corrosion of Ni-Cr alloy decreased with time because the passivation layer was formed on the surface. Under flow conditions, the galvanic current sharply shifted to the negative direction (increase galvanic current from Ni-Cr alloy (anode) to Cu (cathode) during the first few minutes.