Cationized starch-based material as a new ion-exchanger adsorbent for the removal of C.I. Acid Blue 25 from aqueous solutions
ABSTRACT This article describes the use of a cationized starch-based material as new ion-exchanger adsorbent for the removal of C.I. Acid Blue 25 (AB 25) from aqueous solutions. Batch adsorption studies concerning the effects of contact time, pH and temperature are presented and discussed. Adsorption experimental data showed that: (i) the process was uniform and rapid: adsorption of dye reached equilibrium in 50 min in the wide pH range of dye solutions; (ii) adsorption kinetics followed the pseudo-second order model; (iii) the Langmuir model yielded a much better fit than the Freundlich model for the dye concentration range under study; (iv) this adsorbent exhibited interesting adsorption capacities: on the basis of the Langmuir analysis, the maximum adsorption capacity was determined to be 322 mg of dye per gram of material at 25 degrees C; (v) the adsorption capacity decreased with increasing temperature; and (vi) the negative value of free energy change indicated the spontaneous nature of adsorption.
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ABSTRACT: A facile green recipe was developed to synthesise highly pure, safe and durable zinc oxide nanoparticles (ZnO Nps) using homemade starch-rich potato extract. The ZnO Nps were synthesised using zinc nitrate and potato extract, and the whole reaction is carried out for 30 min at 80 °C. In the synthesis, starch-rich potato extract acted as the reducing agent and as a stabilising layer on freshly formed ZnO Nps. Hexagonal (wurtzite) shaped ZnO Nps with size about 20 ± 1.2 nm were synthesised and characterised using X-ray diffraction, transition electron microscope and scanning microscopy analyses. Fourier transform infrared spectral analysis indicated that highly pure ZnO nanopowders were obtained at higher temperatures. The use of environmentally benign and renewable material as the respective reducing and protecting agents, starch-rich potato extract, as well as a gentle solvent medium (H2O), offered a simple and quite efficient procedure for the synthesis of ZnO Nps in neutral medium with promising potential for biological and biomedical applications.Journal of Experimental Nanoscience 05/2015; DOI:10.1080/17458080.2015.1039610 · 1.04 Impact Factor
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ABSTRACT: Three kinds of layered double hydroxides (LDHs), including Ni/Al-LDH, Mg/Al-LDH and Co/Al-LDH, were adopted in this research to study the adsorption process of reactive brilliant red X-3B. Factors affecting adsorption such as contact time and temperature were investigated. The adsorption kinetic data fit well into the pseudo-second-order model, while the adsorption isotherm followed the Langmuir model. The thermodynamic tests indicated spontaneous and exothermic nature of X-3B adsorption. In order to examine the adsorption mechanism, pH effect was investigated and adsorbents and adsorption products of Ni/Al- and Mg/Al-LDHs were characterized further by several physicochemical techniques in view of their relative large capacity. The pH effect tests illustrated that electrostatic reaction and hydrogen bonding between dye molecules and LDH layers may be the major mechanisms involved in adsorption. The FT-IR analysis revealed that there was ion exchange during the adsorption process. The XPS, TG, and NMR experiments further proved that the hydrogen bonding between the adsorbent and adsorbate played the dominant role in this process and the ─SO3 was the interaction site.Applied Surface Science 04/2014; 301. DOI:10.1016/j.apsusc.2014.02.073 · 2.54 Impact Factor
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ABSTRACT: Over a period of 24 months of operation, we optimised a physicochemical plant for the decontamination of surface treatment industrial wastewater. This article presents the abatements obtained in the levels of chemical pollution after the various optimisations validated in the laboratory and then transposed to the industrial site. The optimisation of the plant reduced the effluent organic load, nitrite and zinc levels by about 70%, 85% and 80%, respectively. To evaluate the utility of each optimisation proposal, standard bioassays based on lettuce seed germination were carried out on the final effluent. Decreasing concentrations of pollutants in the effluent led to a reduction of its impact on seed germination. The bioassays confirmed the environmental benefits obtained from the optimisation of the treatment plant. The biological tests proposed seem to be good indicators of the contaminant concentrations present in wastewater.The Canadian Journal of Chemical Engineering 03/2014; 92(3). DOI:10.1002/cjce.21857 · 1.31 Impact Factor