دانلود رایگان مقاله سایش شن و ماسه جهت مدل سازی کمی در ventifacts

 ABSTRACT

In this research, a novel adsorbent, zinc oxide nanoparticle loaded on activated carbon (ZnO-NP-AC) was synthesized by a simple, low cost and efficient procedure. Subsequently, this novel material was characterizated and identified by different techniques such as Brunauer, Emmett and Teller (BET), scanning electron microscopy (SEM), X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FT-IR) analysis. Unique properties such as high surface area (>603 m2 /g) and low pore size (<61 A˚ ) and average particle size lower than 100 A˚ in addition to high reactive atom and presence of various functional groups make it possible for efficient removal of malachite green (MG). In batch experimental set-up, optimum conditions for quantitative removal of MG by ZnO-NP-AC was attained following searching effect of variables such as adsorbent dosage, initial dye concentration and pH. Optimum values were set as pH of 7.0, 0.015 g of ZnO-NP-AC at removaltime of 15 min. Kinetic studies at various adsorbent dosage and initial MG concentration show that maximum MG removal was achieved within 15 min of the start of every experiment at most conditions. The adsorption of MG follows the pseudo-second-order rate equation in addition to interparticle diffusion model (with removal more than 95%) at all conditions. Equilibrium data fitted well with the Langmuir model at all amount of adsorbent, while maximum adsorption capacity was 322.58 mg g1 for 0.005 g of ZnO-NP-AC.

4. Conclusion

This investigation show the efficiency of ZnO-NP-AC as a good, green and low-cost with high adsorption capacity adsorbent (322.58 mg g1 ) for the removal of MG from aqueous solutions in short time (<20 min). In this study, the effective pH was 7 and the optimum adsorbent dose was found to be 0.015 g. Langmuir isotherm gave a better fit to adsorption isotherms than Freundlich isotherm. The kinetic study of MG on ZNO-NP-AC was performed based on pseudo-first-order, pseudo-second-order, Elovich and intraparticle diffusion equations. The results data indicate that the adsorpt follow the pseudo-second-order rate in addition to interparticle diffusion model. The present study concludes that the ZNO-NP-AC could be employed as low-cost adsorbents instead of commercial activated carbon for the removal of MG from water and wastewater. Further studies on quantitative characterization of this adsorbent and involved mechanisms, and feasibility of using this adsorbent for other dyes for possible industrial application are needed.