Monitoring the decolourisation efficacy of advanced membrane fabricated phytosilica nanoparticles in textile effluent water treatment.

Silica nanoparticles are generally mesoporous that are predominant in the sand and rocks. Silica nanoparticles have a wide range of applications in various fields such as medicine, waste management, effluent treatment and electronics. The present work has explored the synthesis of silica nanoparticles through acid and alkaline leaching method from Pedalium murex which is a common weed that is found in southern parts of Tamil Nadu. Silica nanoparticles (SiNps) and its functional groups were confirmed by EDX and FTIR analysis with their respective energy dispersion levels and wavenumbers. Size, shape and morphological features of SiNps were analysed by PSA, TEM and SAED analysis. Synthesised and characterized nanosilica was crosslinked over nylon-66 and cellulose nitrate membranes and were confirmed by FTIR analysis for their crosslinking with SiNps. Water retention activity of the crosslinked and non crosslinked membranes was analysed by contact angle measurement to ensure the receptability of the membranes to remove contaminants by the adsorption. The decolourisation efficiency of the crosslinked nylon 66 membrane was found as a potential source for the treatment with 65.5% colour reduction when compared with other membranes. A slight reduction of solid profiles and COD ranges were achieved for crosslinked membranes than non crosslinked membranes.

Biosynthesised silver and copper nanoformulation as foliar spray to control bird's eye spot disease in tea plantations.

Tea leaves have economic importance in preparation of the popular beverage of the world "tea". Bird's eye spot disease of tea leaves creates significant revenue loss in tea trade of many tea plant cultivating countries. Management of this disease by silver (AgNps) and copper (CuNps) nanoparticles that are biosynthesised by efficient antagonists was studied. The biocontrol agents like Pseudomonas fluorescens, Trichoderma atroviride and Streptomyces sannanensis were evaluated for nanoparticle synthesis against Cercospora theae isolates namely KC10, MC24 and VC38. Initially, the freshly prepared extracellular AgNps showed high disease control (59.42 - 79.76%), but the stability of antagonistic property in stored nanoparticles were significantly high in CuNps (58.71 - 73.81%). Greenhouse studies on various treatments imposed also showed reduced disease incidence percentage of 13.4, 7.57 and 10.11% when treated with CuNps synthesized by P. fluorescens, T. atroviride and S. sannanensis respectively. Various treatment schedule in fields suggested the use of Bionanocopper@1.5 ppm for highest yield (3743 kg/ha) with 66.1% disease prevention. The results suggest the use of biosynthesised CuNps using Streptomyces sannanensis for controlling the tea plant pathogens causing foliar disease with higher stability in releasing the antagonistic activity during sporadic disease incidence of bird's eye spot disease in tea plants.