Activated carbon derived from finger citron residue (FAC) was tested as a new type of adsorbents to remove the harmful dyes (anionic dye methyl orange (MO) and cationic dye methylene blue (MB)) from contaminated water. Liquid phase adsorption experiments were conducted and the maximum adsorptive capacity was determined. Various conditions were evaluated, including initial dye concentration, adsorbent dosage, contact time, solution pH, and temperature. The Langmuir and Freundlich adsorption models were used to describe the equilibrium isotherm and isotherm constant calculation. It was found that the adsorption capacity of FAC is much higher than those of the other types of activated carbons. Maximum equilibrium adsorption capacities of 934.58 mg/g and 581.40 mg/g for MO and MB were achieved.Three simplified kinetic models including pseudo-first-order, pseudo-second-order and intra-particle diffusion equations were used to investigate the adsorption process.The pseudo-second-order equation was followed for adsorption of MO and MB on FAC. Temperature-dependent adsorption behaviors of MO and MB show that the adsorption is a spontaneous and endothermic process accompanying an entropy increases (the driving force of the adsorption). This work indicates that FAC could be employed as a low cost alternative to commercially available activated carbon in the removal of dyes from wastewater.

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Nanothread-based porous spongelike Ni3S2 nanostructures were synthesized directly on Ni foil by using a simple biomolecule-assisted method. By varying the experimental parameters, other novel Ni3S2 nanostructures could also be fabricated on the nickel substrate. The electrochemical hydrogen-storage behavior of these novel porous Ni3S2 nanostructures was investigated as an example of the potential properties of such porous materials. The thread-based porous spongelike Ni3S2 could electrochemically charge and discharge with the high capacity of 380 mAh g(-1) (corresponding to 1.4 wt % hydrogen in single-walled nanotubes (SWNT)). A novel two-charging-plateaux phenomenon was observed in the synthesized porous spongelike Ni3S2 nanostructures, suggesting two independent steps in the charging process. We have demonstrated that the morphology of the synthesized Ni3S2 nanostructures had a noticeable influence on their electrochemical hydrogen-storage capacity. This is probably due to the size and density of the pores as well as the microcosmic morphology of different nickel sulfide nanostructures. These novel porous Ni3S2 nanostructures should find wide applications in hydrogen storage, high-energy batteries, luminescence, and catalytic fields. This facile, environmentally benign, and solution-phase biomolecule-assisted method can be potentially extended to the preparation of other metal sulfide nanostructures on metal substrates, such as Cu, Fe, Sn, and Pb foils.

Octahedral MOF@COF core–shell hetero-framework photocatalysts were designed which achieved superior photocatalytic H2-evolution activity.