ultrasonically assisted removal of toxic dye using iranian bituminous coal based-activated carbon: synthesis, characterization, modeling, equilibrium and kinetic studies

Bituminous coal as an abundant natural resource in iran was successfully employed to facile synthesis nanoparticle and nanosheets of activated carbon (ac) for refinement of methylene blue (mb) effluent. the structural features of prepared carbon nanoparticles and nanosheets were determined by bjh (barret–joyner–halenda), tem (transmission electron microscopy), ftir (fourier transform infrared), sem (scanning electron microscopy) and xrd (x-ray diffraction) analysis. a combination of central composite design (ccd) with response surface methodology (rsm) has been applied to obtain a model and optimize the influencing variables on mb elimination by produced ac. more specifically, the impacts of influencing variables including sonication time, dye concentration, adsorbent mass, and temperature have been inspected. a total of 31 experiment sets were designed to achieve maximum adsorption percentage (r%) and adsorption capacity (qe). the best adsorption percentage, equal to 100%, was obtained under optimum conditions set as 0.20 g of adsorbent, mb concentration of 10.81 mg l−1, temperature equal to 44.2 °c, and 7.3 min of sonication time. the results exhibited that the pseudo-second-order and langmuir model suitably suited to the experimental data of adsorption. the proposed technique in comparison with the recently reported techniques for cationic dye adsorption indicates that the bituminous coal-based ac by utilizing a cleaner production process has several remarkable advantages such as the abundance of raw materials, low cost, ease of production, sustainability, fast adsorption kinetics, and high-performance index.