Removal of emerging micropollutants from water using hybrid material precursor to natural sericite clay

602-610The occurrence of a wide range of micropollutants in natural aquatic environment has been reported in different parts of the world. These compounds are harmful for the aquatic life and human beings. Diclofenac and clofibric acid are the two common toxic micropollutants due to very large production and high consumption by humans. The present communication addresses the removal of diclofenac and clofibric acid from aqueous solutions using the hybrid material obtained by incorporating 3-aminopropyltriethoxysilane (APTES) onto the activated sericite clay. Initially, sericte clay was treated for activation and further modified with organosilane to obtain hybrid material. The materials were characterized using SEM, BET surface area, XRD, and FT-IR analyses. SEM and BET surface area analyses showed that the textural property of sericite clay was greatly changed after activation and the surface area was immensely increased from 3.65 to 62.92 m2/g. The organosilane was anchored on the activated clay and confirmed with FTIR analysis. Batch adsorption experiments showed that the diclofenac and clofibric acid removal is maximum at pH 6.0 to 7.0 and the adsorption of these two micropollutants were observed to be very fast and the time dependent adsorption data were best fitted to pseudo-second order kinetic model. The maximum adsorption capacity of diclofenac and clofibric acid using APTES-sericite hybrid material was found to be 1.868 and 1.749 mg/g, respectively. Furthermore, the loading capacities of the column packed with APTES-sericite hybrid material were found to be 0.789 and 1.095 mg/g. Therefore, this study indicated that the APTES-sericite hybrid material must be an useful material for the effective removal of diclofenac and clofibric acid from aqueous waste

Optimization of solar degradation efficiency of bio-composting leachate using Nd: ZnO nanoparticles

Composting leachate is one of the highly polluted liquids generated at landfills and compost plant. Therefore, the aim of this research work was to photodegrade leachate generated from a biocomposting plant from Iran by neodymium-doped ZnO hybrid nanoparticles (Nd:ZnO NPs). The photocatalytic degradation of leachate was optimized based on surface response methodology. For the experimental design and process optimization, the central composite design was applied. The parameters studied were the dosage of Nd:ZnO NPs, solution pH, contact time, H2O2 concentration, and leachate concentration. Using “ Design Expert software (Trial Version 7.0)”, totally 33 runs were considered for photodegradation studies. Mineralization of the leachate was confirmed by COD analysis. The response was assessed for different models and the high regression coefficient (R2 = 0.9782, Radj = 0.9909) between the variables and the response confirmed excellent estimation of experimental data by quadratic model. The optimum conditions (COD removal efficiency of 82.19) were found to be at pH 6.74, Nd-doped ZnO dosage of 1920 mg/l, leachate concentration of 2000 mg/l, contact time of 114.62 min, the H2O2 concentration of 12.56 Mmole, and dopant percentage of 0.75