AbstractActivated carbon prepared from agricultural byproducts and wastes could be used as an absorbent for dye removal from aqueous solution. Moreover, Vietnam has presently become one of the world's biggest cashew processing countries. Cashew nut shell has been considered as a hazardous solid waste. The wasted cashew nut shell should be used as a low cost source of activated carbon absorbent. The main approaches of this study are to optimize the conditions of activated carbon production from cashew nut shell and understand the adsorption mechanism of how the dye absorb onto cashew nut shell activated carbon. The absorption model developed in this study could be useful guide for assessing the independent impacts as well as the interactions between the impact parameters and give a good idea to enhance the absorption capacity. The experimental data was fitted well to the pseudo‐first and pseudo‐second order as well as the Elovich model at different initial MB concentrations. The inconsistence of the best‐fit‐kinetic model might result in difficulties in comprehensive understanding of adsorption mechanism. Other impacts, such as competitions of components, particle size could be included in next studies to develop the absorption models of the specific activated carbon prepared from cashew nut shell.