Bioremediation potential of arsenic by non-enzymatically biofabricated silver nanoparticles adhered to the mesoporous carbonized fungal cell surface of Aspergillus foetidus MTCC8876.

Our study aiming for the diminution of arsenic concentration in arsenic contaminated aqua environment by using novel adsorbents based on bio-fabricated silver nanoparticles on a fungal cell surface. Bioreduction of silver ion was done in a non-enzymatic manner in presence of the biomass of fungus Aspergillus foetidus MTCC8876. Aspergillus spp. cells were harvested following the bioreduction and made into carbon by carbonization that led to pore formation (pore width of 2.35 nm) on the cell surface. The average size of silver nanoparticles in the sample of SACF (silver nanoparticles adhered to mesoporous carbonized fungal cell) was 35 nm. Whereas mesoporous carbonized control fungal (CCF) cell was devoid of any particles on its surface. For structural characterizations of this adsorbent as well as to emerge its changes as a validation of arsenic adsorption, different biophysical methods such as FTIR, XRD, SEM, FESEM, TEM, BET surface area analysis and SERS analysis were followed. Batch mode experiments were performed to investigate the influence of As (V) concentrations, reaction time, pH of the solution and also the temperature of experiments on the efficiency of As (V) removal by adsorbents SACF & CCF. This arsenic-adsorbent interaction was proved to be endothermic in nature as well as the negative ΔG value indicated the spontaneity. SACF showed exceptional efficiency for the removal (>93%) of arsenic rather than CCF from an aqueous environment within a very short time of 3.5 h due to its porosity and the presence of the silver nanocrystals.