Effect of Ca2+ ions on naphthalene adsorption/desorption onto calcium oxide nanoparticle: Adsorption isotherm, kinetics and regeneration studies.

The adsorptive nature of calcium oxide nanoparticles in aqueous sample of naphthalene in presence of Ca2+ ions was estimated. Enhanced efficiency of calcium oxide regeneration (90%) with the aid of calcium chloride in the solution concentration of 0.002-0.1 M was depicted. The less degree of toxic naphthalene desorption merged with SEM, FTIR and XRD characterization data portrays the importance of naphthalene adsorption onto calcium oxide using calcium chloride for regeneration. Batch adsorption studies were performed to evaluate the operating parameters such as pH, naphthalene concentration, contact time and impact of Ca2+ on naphthalene study. The adsorption isotherm of naphthalene on calcium oxide nanoparticle was described by Langmuir, Freundlich, Temkin and Dubinin Radushkevich and theoretical maximum monolayer adsorption capacity was found to be 63.81 mg/g at 303 K. The adsorption kinetic best fitted with pseudo second order kinetic model. The positive influence of making the addition of Ca2+ ions into naphthalene solution for its rapid adsorption was elucidated which is leaded by a probable increase in sorption capacity for naphthalene molecules at lower concentrations. The stable nature of crystallinity of calcium oxide and a less degree of naphthalene molecules leaching during consecutive cycles of adsorptive process and nanoparticle regeneration was also scrutinized.

Surface-modified nanosilica-chitinase (SiNp-Chs)-doped nano enzyme conjugate and its synergistic pesticidal activity with plant extracts against armyworm Spodoptera litura (Fab.) (Lepidoptera: Noctuidae).

A laboratory experiment was conducted to evaluate enhanced pesticidal activity of silica nanoparticles-doped chitinase nano enzyme conjugate against an economically important insect pest Spodoptera litura (Fab.) (Lepidoptera; Noctuidae). Silica nanoparticles were synthesized by hydrolysis and condensation of precursor tetraethylorthosilicate (TEOS) followed by functionalization with functioning agent 3-aminopropyltriethoxysilane. Functionalized silica nanoparticles thus acquired were doped with chitinase enzyme produced by Serratia marcescens SU05. Doped nanosilica-chitinase nano enzyme conjugate was loaded with pesticidal plant extracts to study the improved pesticidal activity. Synthesized nano enzyme conjugate revealed high stable, monodisperse spherical nanoparticles and exhibited effective loading with respective plant extracts. Nano enzyme conjugates and plant extracts loaded with nano enzyme conjugate recorded high rate of mortality against the larval instars and brought about a distinct effect on the life stage parameters of S.litura. Non-target toxic effect of nano enzyme conjugate was carried out by determination of lethality and changes in protein profiling against brine shrimp (Artemia salina) that shows less lethality and no distinct changes in protein profiling which suggest the effective utilization of silica nanoparticles doped chitinase as an insecticidal agent against economically important insect pests associated with various crops.