جستجوی مقالات مرتبط با کلیدواژه « ni » در نشریات گروه « مهندسی آب »

In this study, bimetallic iron–nickel nanoparticles were obtained by chemical co-deposition of iron chloride with sodium boron hydride used as a strong reducing agent. The bimetallic nanoparticles thus obtained were then used to remove acid red 14 in a slurry system. Experiments were conducted to investigate such parameters as initial dye concentration, nano-particle dosage, pH, the time required for the nano-particles to be used after they are formed, the stirring speed, and the temperature required to reach optimum reaction conditions. Control experiments were subsequently performed under the optimum conditions thus determined to identify any other remaining factors involved. The optimum conditions included a temperature of 25±2 ºC, a newly synthesized nano-particle concentration of 0.05 g/L, an initial dye concentration of 200 mg/L, a pH level of 7.5, and a mixing duration of two minutes. The results indicated the high activity of the nanoparticles such that removal efficiencies equal to 79.39, 90.52, and 94.42 percent were achieved after 2, 30, and 240 minutes, respectively. Moreover, a COD removal of 72.61 percent was achieved after 4 hours of reaction.

This study investigates the potential of nano-zero-valent iron particles coated with nickel in the removal of lead (Pb2+) from porous media. For this purpose, the nano-particles were initially synthesized and later stablilized using the strach biopolymer prior to conducting batch and continuous experiments. The results of the batch experiments revealed that the reaction kinetics fitted well with the pseudo-first-order adsorption model and that the reaction rate ranged from 0.001 to 0.035 g/mg/min depending on solution pH and the molar ratio of Fe/Pb. Continuous experiments showed that lead remediation was mostly influenced not only by seepage velocity but also by the quantity and freshness of nZVI as well as the grain type of the porous media. Maximum Pb2+ removal rates obtained in the batch and lab models were 95% and 80%, respectively. Based on the present study, S-nZVI may be suggested as an efficient agent for in-situ remediation of groundwater contaminated with lead.

In this study, the in-situ application of nano zero valent Iron/Nickel particles for Nitrate removal in groundwater resources was investigated. First, nano-particles were produced and stabilized with starch. Second, it was employed in batch and continuous experiments, using transparent column and bench-scale models. Based on batch experiments, the reaction kinetics was consistent with the adsorption model by the order of 1 to 1.3. The variation of the kinetics order depends on pH and Nickel content. So that highest reactivity was observed for Iron nano particles with 3% of Nickel. Based on continuous experiments, a seepage velocity of 10 m/d yielded the maximum removal efficiency. Furthermore, Nitrate remediation in a continuous system was mostly influenced by seepage velocity, quantity and freshness of nano particles, and grain size of porous media. In the batch mode, the maximum Nitrate removal was 99% while in the continuous mode it did not exceed 70%.

One of the main sources of environment pollution is the industrial wastewater which contains heavy metals and can be found in many industries such as plating industry. If these heavy metals enter in the human body, would cause many health problems. The aim of this study was to investigate the possible application of nanofiltration technology in removal of three heavy metals (nickel, zinc, and cupper) as the most representatives of heavy metals in plating effluents. The effects of different pressure, concentration, and time of filtration on removal of these elements were evaluated. Two concentrations levels of heavy metals (25 and 50 mg/L) were studied under three different pressures of 4, 6 and 8 bar. pH and temperature were considered constant in all experiments. The results showed that increasing of pressure resulted in increased in removal. This was more significant for Cu (100% removal) than Zn and Ni under 8 bar of pressure. Also, it was found increasing of concentration resulted in decreased removal of heavy metals. The results showed that Zn removal decreased from 99% in 25 mg/L to 97. 07% in 50 mg/L. Finally, the filtration time caused a positive effect in the heavy metals removal