A large number of wastewater is produced in the process of electroplating industry, and pose serious threats to humanity. Nanoscale zero valent iron (nZVI) has a desirable reductive adsorption ...capacity for treatment of the electroplating wastewater, but limited by its agglomeration and oxidation. In this study, the composite material nZVI@B was prepared using the emulsion of nZVI and sodium bentonite, and characterized by scanning electron microscopy, X-ray diffraction, and X-ray photoelectron spectroscopy. The aggregation and oxidation phenomena of nZVI particles were decreased with the successfully supported on bentonite. The decontamination abilities of nZVI@B were tested by removal of nickel (Ni) from the electroplating wastewater. The results showed that the nZVI@B has a 99.96% removal efficiency at 120 min, which is greatly better than those of nZVI and bentonite. The reactivity of the nZVI can be effectively improved by dispersed in the interlayer of Bentonite and reduced to contact with water. The lower solution pH value, initial concentration, and higher dosage had positive effects on Ni removal. But the effect of temperature on final removal efficiency was not remarkable. Furthermore, the tailings obtained though the batch experiments were detected by energy-dispersive X-ray spectroscopy, the content of Ni is in the range from 25% to 40%, which can reduce the total amount of tailing slag treatment and the difficulty of recycling.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
One of the most important steps in the zinc processing industries is the removal of impurities. In this step, cobalt, nickel and cadmium are removed from the leach solution by hot and cold ...purification, respectively. In this research, the effective parameters on cold purification reactor of Dandi zinc smelting plant (Zanjan—Iran) such as temperature, consumption of zinc dust, residence time, copper sulfate additive, pH of solution, zinc dust particle size and mixing speed are studied. Results demonstrated that optimum concentration of zinc dust to remove impurities properly is 2 g/L, which is less than the factory’s consumption by up to 30%. It was also found that the copper sulfate had no effect on the removal process of nickel and cadmium, and hence exclusion of this additive can cause cost-effectiveness in the process. Optimum amounts of residence time, temperature, pH and mixing speed are 75 min, 80 °C, 4.5 and 400 rpm, respectively. It was demonstrated that the smaller particle size has more effect on the removal of nickel and cadmium. The maximum efficiency was observed at < 45 µm. More ever, the high density of zinc ions had a deterrent effect on the efficiency of nickel and cadmium removal.
Studies on the removal of nickel(II) ions by adsorption on various carbons (commercial activated carbon (CAC) and chemically prepared ACs (CPACs) from raw materials like straw, saw dust and dates ...nut) have been carried out under batch mode of adsorption at 30 degree C with an aim to obtain information on treating effluents containing Ni(II) ions. The effect of various experimental parameters such as (i) initial concentration (ii) contact time, (iii) dose of adsorbent, (iv) initial pH of the solution, with CAC and CPACs, (v) particle size of CPACs (except CAC) and (vi) ionic strength (with CAC and CPACs) at 200 rpm speed of agitation has been investigated. The percentage removal of Ni super(2+) ions increased with the decrease in initial concentration and particle size of the adsorbent and increased with the increase in contact time, dose of adsorbent and initial pH ( delta ) of the slurry. Ionic strength decreased the extent of adsorption. The adsorption data were modelled with the Freundlich, Langmuir, Dubinin-Radushkevich and Redlich and Paterson adsorption isotherms and first-order kinetic equations such as of Natarajan and Khalaf, Lagergren, Bhattacharya and Venkobachar and modified Elovich equations and intra-particle diffusion model. The kinetics of adsorption is found to be of first order with intra-particle diffusion as one of the rate determining steps. Thermodynamic parameters were evaluated from the equilibrium studies carried out at 30 degree , 35 degree and 40 degree C. Investigations on the desorption of Ni(II) ions from metal loaded ACs with various eluents and the possibility of reuse of regenerated ACs have also been carried out at 30 degree C. The results on the removal of Ni(II) ions by CPACs are compared with CAC and cationic resin, Tulsion CXO-9(H). The results conclude that these carbons could be employed as low-cost alternative adsorbents to CAC in wastewater treatment for the removal of metal ions, in general, and nickel(II) ions, in particular.
Cilj je rada ispitati djelotvornost neobrađene i kemijski obrađene komercijalne čađe za uklanjanje toksičnih iona nikla iz vodenih otopina. Kemijska obrada provedena je adsorpcijom organskih kiselina ...na čađi. Dobiveni rezultati pokazali su da karboksilne skupine adsorbiranih kiselina uspješno modificiraju površinu čađe. Na taj način obrađena čađa postala je djelotvornija za uklanjanje iona nikla iz vodenih otopina.
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