The processes involved to extract chitosan biopolymers from natural resources often employ hazardous chemicals and long processing time. This work provides a sustainable direct extraction method of chitosan from snail shells. Previous attempts using acetogenin in graviola extracts succeeded in the extraction of chitosan from marine shells. However, the slow reaction has prompted the addition of hydrogen bond acceptor solution into the graviola extract. Choline chloride is an excellent hydrogen bond acceptor mixed with acetogenin as hydrogen bond donor to form natural deep eutectic solvent (NADES) for the direct extraction of chitosan. Chitosan obtained from this method has a degree of deacetylation of 91% and a molecular weight of 481 kDa with fiber-like morphology. The direct extraction of chitosan from NADES consisting of choline chloride and acetogenin has proven to extract chitosan with comparable properties to commercial chitosan.

The aim of this study was the investigation of how adsorbents made from Leucaena leucocephala (L. Leu) leaf and bark materials were effective in treating wastewater containing methyl red dye (MeReD). The functional groups in the phytochemical elements from the bark and leaves of L.Leu offer active surface sites and enable the adsorption mechanism. The investigations were done in batch mode. Contact time, adsorbent dose concentration, temperature, pH, and initial MeReD concentration were all examined as significant parameters impacting the sorption process. The study found that significant MeReD removal efficiency was achieved after 90 min of contact time, pH 4.0 units, 1.2 gm/L adsorbent dose concentration, 100 ppm initial MeReD quantity, and 30 oC temperature. The developed adsorbents were applied to samples gathered from dye companies in Hyderabad and Guntur. The extraction of MeReD (81.2% to 90.0%) from untreated wastewater contaminated with MeReD using developed adsorbents was very efficient.

An analytical procedure for the analysis of carotenoids in marine sediments rich in organic matter has been developed. Analysis of these compounds is difficult; the application of methods used by other authors required optimization for the samples studied here. The analytical procedure involved multiple ultrasound-assisted extraction with acetone followed by liquid-liquid extraction (acetone extract:benzene:water - 15:1:10 v/v/v) and HPLC analysis. The influence of column temperature on pigment separation and the quantification method were investigated – a temperature of 5 °C was selected for the Lichrospher 100 RP-18e column. The pigments in the sediment extract were quantified using a method based on HPLC analysis (at 450 nm) and spectrophotometric measurements (at 450 nm), and extinction coefficients were determined for standard solutions at this wavelength. It is very important to use the value of the extinction coefficient appropriate to the wavelength at which the detection of carotenoids was carried out.