Adsorption of nitrobenzene (NB) from aqueous solution onto mesoporous silica materials, i.e., pyrolyzed MCM-41 (Si-C), pyrolyzed Al-MCM-41 (Al -C), MCM-41 containing g-C3N4 (Si-C-3), and Al-MCM-41 containing g-C3N4 (Al-C-3) were investigated. Results indicated that NB adsorption was fast, and the adsorption process reached a steady state in under 5 min. The adsorption data were tested by Langmuir, Freundlich, and Redlich-Peterson isotherm models, and the Langmuir isotherm was found to provide a better fit with the experimental data. The maximum adsorption capacities of various sorbents Al-C, Si-C, Al-C-3, and Si-C-3 were 243.9 mg/g, (1982 mu mol/g), 217.4 mg/g (1767 mu mol/g), 116.3 mg/g (945.1 mu mol/g), and 54.95 mg/g (446.5 mu mol/g), respectively.