Malachite green (MG) is widely used as a textile dye and an aquacultural biocide, and become a serious pollution of drink water, but effectually isolating and removing it from wastewater are still a challenge. Here we report a new strategy to prepare a carbon foam with tunable pore size distribution by a one-pot lava foam process. We find that uniform micropore size is beneficial to the formation of C-OH coordination on the pore surface, increasing MG adsorption rates via H+ ionization. As a result, carbon foam with uniform pore size distribution demonstrates an optimum MG removal efficiency of 1812 mg g-1 and a higher partition coefficient of 3.02 mg g-1 μM-1, which is twice that of carbon foams with irregular pore size distribution. The adsorption of MG onto these adsorbents was found to be an endothermic monolayer chemical adsorption process, and the Gibbs free energy of adsorption process was decreased obviously by regulating micropore size distribution. The experiment results are in good agreement with pseudo-second-order kinetic and Langmuir isotherm models. Revealed the pore size distribution was the critical factor of MG removal by carbon foam. It should be and inspiration for the design and development of highly efficiency adsorbents for dyes removal.
Keywords: Adsorption; Malachite green; Porous carbon foam; Pyrolysis; Sucrose.
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