SnO2 nanoparticle-loaded activated carbon for simultaneous removal of Acid Yellow 41 and Sunset Yellow; derivative spectrophotometric, artificial neural network and optimization approach.

The simultaneous adsorption of Acid Yellow 41 (AY41) and Sunset Yellow (SY) onto SnO2 nanoparticle-loaded activated carbon (SnO2-NP-AC with very high BET surface area of 1278.71 m(2) g(-1)) was investigated. To overcome the severe dyes spectral overlapping, derivative spectrophotometric method and principal component analysis-artificial neural network (PCA-ANN) were successfully applied for the simultaneous determination of AY41 and SY in their binary solutions. By using central composite design (CCD) under response surface methodology, the effects of variables such as contact time, adsorbent dosage, pH, AY41 concentration and SY concentration on responses such as binary dyes removal percentages were examined. Optimal values were found to be 17.9 min, 0.024 g, 3.1, and 15.9 mg L(-1) and 18.7 mg L(-1), respectively. In binary solutions, the best fit to modified-extended Langmuir isotherm was obtained for the whole concentration range. In binary solutions, a synergism was observed for the AY41 and SY dyes adsorption onto SnO2-NP-AC. The adsorption rates at various times were analyzed. It indicated a pseudo-second-order kinetic model for the adsorption of both dyes.

Comparative studies on removal of Erythrosine using ZnS and AgOH nanoparticles loaded on activated carbon as adsorbents: Kinetic and isotherm studies of adsorption.

Erythrosine adsorption (Er) onto ZnS and AgOH nanoparticle-loaded activated carbon (ZnS-NP-AC and AgOH-NP-AC) was studied and results were compared. Subsequent preparation were fully analyzed by different approach such as BET to obtain knowledge about surface area, pore volume, while FT-IR analysis give comprehensive information about functional group the dependency of removal percentage to adsorbent mass, initial Er concentration and contact time were investigated and optimum conditions for pH, adsorbent dosage, Er concentration and contact time was set as be 3.2, 0.016g, 20mg/L and 16min and 3.2, 0.015g, 19mg/L and 2min for ZnS-NP-AC and AgOH-NP-AC, respectively. The equilibrium data correspond to adsorption strongly follow Langmuir model by ZnS-NP-AC and Freundlich model for AgOH-NP-AC. High adsorption capacity for of 55.86-57.80mgg(-1) and 67.11-89.69mgg(-1) for ZnS-NP-AC and AgOH-NP-AC, respectively. The result of present study confirm the applicability of small amount of these adsorbent (<0.02g) for efficient removal of Er (>95%) in short reasonable time (20min).

Synthesis of nickel sulfide nanoparticles loaded on activated carbon as a novel adsorbent for the competitive removal of Methylene blue and Safranin-O.

Nickel sulfide nanoparticle-loaded activated carbon (NiS-NP-AC) were synthesized as a novel adsorbent for simultaneous and rapid adsorption of Methylene blue (MB) and Safranin-O (SO), as most together compounds in wastewater. NiS-NP-AC was characterized using different techniques such as UV-visible, Fourier transform infrared spectroscopy (FTIR), energy-dispersive X-ray spectroscopy (EDX), X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM) and Brunauer-Emmett-Teller (BET). The surface area of the adsorbent was found to be very high (1018m(2)/g according BET). By using central composite design (CCD), the effects of variables such as pH, adsorbent dosage, MB concentration, SO concentration and contact time on binary dyes removal were examined and optimized values were found to be 8.1, 0.022g, 17.8mg/L, and 5mg/L and 5.46min, respectively. The very short time required for the dyes removal makes this novel adsorbent as a promising tool for wastewater treatment applications. Different models were applied to analyze experimental isotherm data. Modified-extended Langmuir model showed good fit to equilibrium data with maximum adsorption capacity at 0.022g of adsorbent. An empirical extension of competitive modified-extended Langmuir model was proposed to predict the simultaneous adsorption behavior of MB and SO. Kinetic models were applied to fit the experimental data at various adsorbent dosages and initial dyes concentrations. It was seen that pseudo-second-order equation is suitable to fit the experimental data. Individual removalof each dye was also studied.