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Highly efficient adsorbent was prepared for the removal of carbofuran and imidacloprid pesticides from wastewater. The silica monolith anchored graphene oxide composite was synthesized by the modified Fischer esterification protocol. The composite showed improved adsorption capacity for the removal of pesticides from wastewater. Graphene oxide was synthesized using the modified Hummer's method, while the silica monolith was prepared via sol–gel method. The composite was characterized via X-ray diffraction, Fourier transform infra-red, Brunauer Emmett and Teller (BET/BJH) analysis, zeta potential, and FESEM imaging. Different adsorption parameters such as pH, contact time, adsorbate and adsorbent concentration, and temperature were optimized for the adsorption of pesticides. The equilibrium and kinetic models were applied to the adsorption process of the pesticides. Qe of the composite as found to be 342.46 mg g−1 for imidacloprid and 37.15 mg g−1 for carbofuran. The adsorption process followed the pseudo 2nd order kinetic model for carbofuran (R2~0.9971) and imidacloprid (R2~0.9967). The Freundlich isotherm best fitted to the adsorption data of the pesticides with R2 value of 0.9956 for carbofuran and 0.95 for imidacloprid. The resultant adsorbent/composite material came out with very good results for the removal of pesticides. [ABSTRACT FROM AUTHOR]

The ligand 2,6-bis(E)-4-methylbenzylidine)-cyclohexan-1-one sensor has been synthesized as a fluorescence-on sensor/probe for the trace level detection of chromium III ion. The synthesized ligand was characterized by FTIR, 1H-NMR spectroscopy, and fluorimetery. The sensor exhibited an ultra-selective response to chromium among the tested heavy metal ions. Different parameters were optimized like pH, effect of concentration of sensor C, metal ion and contact time. The binding stoichiometry of C:Cr3+ was calculated to be 2:1 (Job's plot) with a significantly low detection limit of 2.3 × 10− 9 M. Sensor C were practically employed for detection of chromium in spiked water samples. [ABSTRACT FROM AUTHOR]