Removal of Reactive Black 5 (RB5) dye from an aqueous solution was studied by its adsorption on banana peel biochars (BPBs). The factors affecting RB5 dye adsorption such as pH, exposure time, RB5 dye concentration, adsorbent dose, particle size and temperature were investigated. Maximum 97% RB5 dye removal was obtained at pH 3 with 75 mg/L adsorbate concentration by banana peel biochars. Fourier transform infrared (FTIR) and scanning electron microscopy (SEM) were used to characterize the adsorbent material. The data of equilibrium were analyzed by Langmuir and Freundlich isotherm models. The experimental results were best reflected by Langmuir isotherm with maximum 7.58 mg/g adsorption capacity. Kinetic parameters were explored and pseudo-second order was found suitable which reflected that rate of adsorption was controlled by physisorption. Thermodynamic variables exhibited that the sorption process was feasible, spontaneous, and exothermic in nature. Banana peel biochar showed excellent regeneration efficiency up to five cycles of successive adsorption-desorption. Banana peel biochar maintained >38% sorption potential of RB5 dye even after five cycles of adsorption-desorption. The phytotoxic study exhibited the benign nature of BPB-treated RB5 dye on tomato seeds.

Nature has always inspired innovative minds for development of new designs. Animals and plants provide various structures with lower density, more strength and high energy sorption abilities that can incite the development of new designs with significant properties. By observing the important functions of biological structures found in nature, scientists have fabricated structures by bio-inspiration that have been proved to exhibit a significant improvement over traditional structures for their applications in the environmental and energy sector. Bio-fabricated materials have shown many advantages due to their easy synthesis, flexible nature, high performance and multiple functions as these can be used in light harvesting systems, batteries, biofuels, catalysis, purification of water, air and environmental monitoring. However, there is an urgent need for sensitive fabrication instruments that can synthesize bio-inspired structures and convert laboratory scale synthesis into large scale production. The present review highlights recent advances in synthesis of bio-inspired materials and use of hierarchical nanomaterials generated through biomolecular self-assembly for their use in removal of environmental contaminants and sustainable development.