Net-like porous activated carbon materials from shrimp shell by solution-processed carbonization and H3PO4 activation for methylene blue adsorption

Abstract

In this work, shrimp shell waste was used as a novel precursor for the production of a net-like porous activated carbon by solution-processed carbonization and chemical activation with phosphoric acid (H3PO4). The H3PO4 activation of activated carbon from shrimp shell (PS-Ac) was characterized in terms of textural, surface and morphological properties by N2 sorption, Raman, HR-TEM and SEM-EDS analyses. It showed that PS-Ac was a net-like porous material with mesoporous structures. The average pore size and BET surface area were 4.5nm and 560.6m2g−1, respectively. The obtained PS-Ac was then employed for the adsorption of methylene blue (MB) dyes and systematically investigated the effect of solution pH, initial concentration, contact time and temperature for MB adsorption. Experimental data were well described by the Langmuir isotherm and the pseudo-second order model with the maximum adsorption capacity of 826mgg−1(MB), which showed to be high compared to other ACs reported in the literature. Thermodynamic parameters indicated that PS-Ac for MB adsorption process was spontaneous and endothermic. Moreover, coupled with experimental results, FT-IR and XPS analysis suggested that the adsorption mechanism of MB onto PS-Ac was possible attributed to electrostatic interaction between the surface of functional groups (PO43−, COO−, O) on adsorbent and the cation ions MB-N+ in the basic solution.