UV-assisted photo-catalytic degradation of anionic dye (Congo red) using biosynthesized silver nanoparticles: a green catalysis

A review of the phytochemical mediated synthesis of AgNP (silver nanoparticle): the wonder particle of the past decade

“…No. Plant Plant part Size (nm) shape Degradation Dye Concentration Efficiency References 1 Azadirachta indica Leaf extract 11–35 Spherical Photocatalytic Congo red 20 mg L −1 90% Shaikh et al ( 2018 ) 2 Shorea robusta Leaf extract 12–37 Spherical Photocatalytic Rhodamine B 21 mg L −1 90.41% Shaikh et al ( 2020 ) 3 Gmelina arborea Fruit extract 8–32 Spherical Catalytic Methylene Blue 100% Saha et al ( 2017 ) 4 Camellia japonica Leaf extract 12–25 Spherical Photocatalytic Eosin-Y 10 mg L −1 > 97% Karthik et al ( 2017 ) 5 Ficus panda Leaf extract 12–36 Spherical Catalytic Methylene blue …”

“…2 ). These photogenerated species (h + VB and e − CB ) generate highly reactive radicals capable of dye degradation (Shaikh et al 2018 ). For example, h + VB can dissociate water (H 2 O) into hydrogen (H + ) and hydroxyl ( − OH) ion, where the hydroxyl ( − OH) ion is subsequently convertedinto a hydroxyl radical ( · OH) (Eq.…”

“…Another extraction method invlolves grinding the fresh plant part after thorough washing with millipore water and/or ethanol. The extract is finally filtered using Whatman filter paper no.1 and stored at 4 °C for further use (Shaikh et al 2018 , 2020 ; Mondal et al 2021 ). Reaction: The last step of the biosynthesis process is the reduction process where the plant extract is added to 1–10 mM AgNO 3 to reduce the pure Ag(I) ions to Ag(0) at room temperature normally in a reaction lasting upto 6 h. Typically, the bio-reduction process is monitored by measuring the UV–visible spectrum at 200–800 nm with a regular interval of 0.5 nm, where the AgNP peak arises around 400–450 nm (Mondal et al 2019 , 2021 ; Shaikh et al 2020 ).…”

“…In some fields, advancements have been remarkable, incluing the use of semiconductor NPs for water splitting (Hisatomi et al 2014 ), various environmental applications (Mondal et al 2021 ), medical application (Gujrati et al 2014 ), and application in electronic fild like sensor (Ahmad et al 2011 ). Amongst the metallic NPs, silver nanoparticles (AgNPs) have been applied most beneficially across a variety of diverse application fields due to their unique biological, chemical, and physical properties including excellent catalytic activity, chemical stability, high electrical conductivity, optical and thermal properties (Shaikh et al 2018 ). Consequently, amongst the metallic NPs, AgNPs have become one of the most significant nanomaterials attracting tremendous research interest.…”

“…Today a wide variety of synthetic methods have been established including chemical methods (Iravani and Zolfaghari 2013 ), electrochemical (Lim et al 2006 ), microwave-assisted synthesis (Darmanin et al 2012 ), photochemical reductions (Remita et al 2007 ) and physical synthesis (Ashkarran 2010 ). All of these methods have their specific own limitations, such as the use of toxic chemicals as reducing and/or stabilizing agent, the requirement for high vacuum technology or other expensive equipment, production of impure AgNPs of very low yield, and high operating costs (Shaikh et al 2018 ). For these reasons there is still a need to develop alternative synthetic routes for AgNP.…”