Accurate assessment and monitoring of coastal and inland water quality by satellite optical remote sensing is challenging due to improper atmospheric correction algorithm, inaccurate quantification of in-water constituents' concentration and a lack of efficient models to predict the water quality status. The present study aims to address the latter two parts in conjugation with an appropriate atmospheric correction algorithm to assess trophic status and water quality conditions of two coastal lagoons using Landsat-8 OLI data. Three vital underwater light attenuating factors, directly related to water quality, are considered namely, turbidity, chlorophyll and colored dissolved organic matter (aCDOM). These water quality parameters are quantified based on certain sensitive normalised water-leaving radiance band ratios and threshold values. To assess the accuracy of the derived products, these algorithms were applied to independent in-situ data and statistical evaluation of the results showed good agreement between the estimated and measured values with the errors within desirable limits. Being a primary nutrient indicator, the chlorophyll concentration was used to evaluate Trophic State Index. The Water Quality Index was derived from three parameters namely, chlorophyll concentration, turbidity and aCDOM(443) which were expressed in terms of Trophic State Index, Turbidity Index and Humic-Fulvic Index, respectively. The Water Quality Index maps, derived using a Fuzzy Inference System based on the Centre of Gravity method, provided insights into spatial structures and temporal variability of water quality conditions of the coastal lagoons which are influenced by anthropogenic factors, hydrographic changes and land-ocean-atmospheric interaction processes.
A facile approach has been chosen for the synthesis of PVDF based copolymer anion exchange membrane using nonhazardous chemicals. The synthetic route was achieved through free radical polymerization between dehydrofluorinated PVDF-co-HFP (DYPVDF) and morpholine functionalized vinyl benzyl chloride (VBC). The variations in properties of formed membranes were evaluated by varying the concentration of VBC. FT-IR, as well as 1H NMR, confirms the formation of the desired molecular structure of copolymer in form of a membrane. Surface morphology of copolymer anion exchange membranes was checked through TEM and AFM analysis. Standardized techniques were used to evaluate the physicochemical and electrochemical properties of the membranes like ion exchange capacity (IEC), water uptake (WU), ionic conductivity (IC) and linear expansion ratio (LER). The highest value of water uptake and IEC was found to be 28% and 1.27?meq/g for PQM-40 copolymer anion exchange membrane. Membranes were subjected to Fenton's test to evaluate their oxidative stability. Maximum weight loss of 1.67%, 1.44% and 1.39% was found in PQM-40, PQM-30, and PQM-20 respectively. Further, synthesized copolymer membranes were subjected to salt removal by electrodialysis and acid recovery by diffusion dialysis (DD). Maximum current efficiency during desalination and highest separation factor for acid recovery by diffusion dialysis were confirmed by PQM-40, the values are 82.36% and 25% respectively.