The surface of the bottle gourd shell (BGS), a solid agricultural residue of Lagenaria vulgaris Ser. was chemically modified using a cationic surfactant, hexadecyltrimethylammonium chloride (HTAC). The success of the modification was confirmed by FTIR spectroscopy. Chemical characterization of the lignocellulosic BGS biomass and the surfactant modified bottle gourd shell (MBGS) was carried out using the compositional and elemental analysis. The amount of surfactant sorbed on the BGS surface was measured as a function of the surfactant bulk concentration. Sorption isotherms were used to verify self-assembly models of cationic surfactant sorption onto oppositely charged MBGS substrates. The shape of sorption isotherms was applied to describe the behavior of the surfactant/BGS system. The surfactant modified shell was tested as a sorbent for the removal of phosphate and nitrate from contaminated aqueous solutions. The sorption of anionic pollutants on MBGS was performed in a series of batch sorption experiments at 20 o C. It was found that the MBGS yielded sorption efficiency was 40% for phosphate and 22% for nitrate. The sorption mechanism involving the ion exchange might be responsible for the uptake of anions. The morphology and surface properties of the MBGS sorbent before and after sorption of anionic pollutants were analyzed by SEM methods. Compared to other non-surfactant sorbents, the advantage of MBGS as a sorbent is that it can be used for the removal of anionic pollutants not only from aqueous solutions but also from the emulsified oil wastewater or nonpolar effluents.

Article Highlights • A new low-cost and efficient cationic biosorbent for phosphate is presented • Phosphate biosorption process is essentially exothermic and spontaneous • The anion exchange mechanism is the dominant biosorption process • Freundlich isotherm describes favorable multilayer phosphate biosorption • Biosorbent can be easily separated, recycled, and reused multiple times

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The structural performance and biosorption behavior of a new cationic biosorbent (CALV) prepared from bottle gourd (Lagenaria vulgaris) shell (LVS) as a potentially valuable agrowaste have been established. The biosorbent with anion exchangeable function was synthesized from a modified lignocellulosic biomass (MLV) by a quaternary ammonium agent, N-(3-chloro-2-hydroxypropyl)trimethylammonium chloride. Preparation of the appropriate MLV precursor was firstly carried out by the process of alkaline pretreatment of LVS biomass using a green carbonate solution. In this way, partial delignification, removal of extractive substances, and increased porosity of the cellulose-enriched MLV biomass, as well as the activation of available cellulosic microfibrils to alkaline-cellulose have been achieved. The optimization of synthesis conditions was carried out by direct estimation of the CALV biosorption efficiency to phosphate (using ICP-OES) and nitrate (using UV-VIS) from the aqueous solutions. The structural changes of MLV precursors during green modification and the success of synthesis and biosorbent performances before and after the removal of anions from contaminated solutions have been registered and clarified by physicochemical methods, which include elemental analysis, chemical constitution, morphological characterization, and FTIR spectroscopy. In accordance with the FTIR spectroscopic analysis and isotherm studies, a structural model of the CALV biosorbent and its ion exchange mechanism are proposed.

Uklanjanje hidrolizovane reaktivne boje važna je faza rada u bojenju pamuka jer utiče na eksploataciona i higijenska svojstva tekstilnih proizvoda. Kao veliki potrošač vode i hemikalija ovaj radni proces proučava se sa aspekta uštede prirodnih resursa i zaštite životne sredine. U ovom radu pruočavan je učinak sredstava za pranje na bazi tenzida različitog jonogeniteta kao i čiste vode na uklanjanje hidrolizovanih reaktivnih boja različitih funkcionalnih grupa. Dobijeni rezultati upućuju na zaključak da čista voda pri većem odnosu kupatila (1:30) i vremenu pranja 30 min može biti efi kasno sredstvo za uklanjanje hidrolizovane monoreaktivne boje. Kod uklanjanja hidrolizovane bifunkcionalne boje pored odnosa kupatila i vremena pranja i koncentracija tenzida može da ima značajan uticaj na učinak procesa.