| Summary: | The rubber (Hevea brasiliensis) seed shell, which is an agricultural waste, was carbonized by one-step liquid phase activation with H2SO4 to be a potential bio-char adsorbent for methylene blue (MB) adsorption from aqueous solution. Carbonized rubber seed shell (CRSS) was characterized by a CHNS-O, Brunauer–Emmett–Teller (BET), X-ray diffraction, Fourier transform infrared spectroscopy, scanning electron microscope with an energy dispersive X-ray spectrometer (SEM–EDX), point-of-zero charge (pHpzc), and proximate analyses. Batch mode adsorption studies were conducted by varying operational parameters such as adsorbent dosage (0.02–0.30 g), solution pH (3–11), initial MB concentrations (50–300 mg/L) and contact time (0–1,440 min). The equilibrium data were well correlated by Langmuir isotherm compared with Freundlich and Temkin models. The maximum adsorption capacity, qmax, of CRSS for MB adsorption was 208.3 mg/g at optimum pH 8 and temperature 303 K. The kinetic uptake profiles are well described by the pseudo-second-order model. All results mentioned above revealed that the CRSS can be feasibly utilized for the removal of MB from aqueous solution. © 2018 Desalination Publications.
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