Abstract
Increases in biological and non-biological pollutants pose a significant threat to environmental systems. In an effort to develop an effective means to treat such pollutants, the use of Phaseolus vulgaris (kidney beans) as reducing and capping agents is proposed for the green synthesis of highly stable silver nanoparticles (AgNPs) with a face-centered cubic (fcc) crystalline structure (size range: 10–20 nm). The potent role of the resulting AgNPs was found as triple platforms (photocatalyst, catalyst, and antimicrobial disinfectant). AgNPs were able to photocatalytically degrade approximately 97% of reactive red-141 (RR-141) dye within 150 min of exposure (quantum efficiency of 3.68 × 10-6 molecule.photon-1 and a removal reaction kinetic rate of 1.13 × 10-2 mmol g−1 h−1). The role of specific reactive oxygen species (ROS) in the photocatalytic process and complete mineralization of dye was also explored through scavenger and chemical oxygen demand (COD) experiments, respectively. As an catalyst, AgNPs were also capable of reducing 4-nitrophenol to 4-aminophenol within 15 min. Overall, AgNPs showed excellent stability as catalyst and photocatalyst even after five test cycles. As an antimicrobial agent, the AgNPs are effective against both gram-positive (Bacillus subtilis) and -negative bacteria (Escherichia coli), with the zones of clearance as 15 and 18 mm, respectively. Thus, the results of this study validate the triple role of AgNPs derived via green synthesis as a photocatalyst, catalyst, and antimicrobial agent for effective environmental remediation.
Highlights
The continuous growth of global population coupled with industrialization and urbanization has brought rising demand for chemicals, materials, and energy
The bacteria E. coli (DH-5α) and B. subtilis were procured from the Department of Biotechnology, SGGSWU, Punjab, India
Addition of the 1, 2, 3, and 4 mL of P. vulgaris seed extract to AgNO3 solution at room temperature changed the appearance of the solution from colorless to pale yellow and to a dark brownish-red color
Summary
The continuous growth of global population coupled with industrialization and urbanization has brought rising demand for chemicals, materials, and energy. Several physical and chemical methods have been explored for the synthesis of AgNPs by employing organic and inorganic stabilizing/ capping agents (Reverberi et al, 2016; Van Dong et al, 2012; Wani et al, 2011; Zhang et al, 2016) These approaches often use noxious and expensive chemicals, involve complex and/or time-consuming processes, and may generate toxic wastes and by-products. AgNPs can be produced through a variety of green synthesis routes if one can effectively utilize the biomolecules (e.g., proteins and vitamins) and phytochemicals (e.g., phenols and flavonoids) within plants (biomass) as natural reducing and capping agents (Raveendran et al, 2003; Singh et al, 2018a; Yadi et al, 2018) This eliminates the need for harmful and expensive chemicals in reduction of metal salts and capping of NPs (as is the case in chemical reduction methods). Studies on the ROS and chemical oxygen demand (COD) were carried out to support the verification of their remediation potential and recyclability/reusability
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
