Development of biological macroalgae lignins using copper based metal-organic framework for selective adsorption of cationic dye from mixed dyes.

The chemical compositions of macroalgae are protein; cholesterol, fatty acid, and lignin which mostly construct from hydroxyl and amine groups. The lignin as a key structure in the tissues of macroalgae was modified using the sulfation pathway. A novel environmental friendly adsorbent Cu-BTC@Algal was synthesized by incorporated Cu-BTC nanoparticles onto sulphated-Macroalgae biomass under solvothermal conditions and characterized by XRD, FTIR, and N2 adsorption-desorption isotherms. The removal rate of Cu-BTC@Algal was quite greater than that of Cu-BTC, showing that the adsorption performance of porous Cu-BTC can be improved through the modification of algal. Further study revealed that Cu-BTC@Algal exhibited a fast adsorption rate and selective adsorption ability towards the cationic dyes in aqueous solution. The removal rate was up to 97% for cationic dyes methylene blue (MB) and 68% for methyl orange (MO) at intervals 10 min. The influences including initial concentration, and contact time of MB/MO adsorption onto modified algal biomass, Cu-BTC and Cu-BTC@Algal were investigated in detail. The kinetic study indicated that the adsorption of MB/MO onto Cu-BTC@Algal followed the pseudo second-order model. The isotherm obtained from experimental data fitted the Langmuir model, yielding maximum adsorption capacity of 42, 73 and 162 mg g-1 for algal, Cu-BTC and Cu-BTC@Algal, respectively.