Removal of nitrophenols from water using cellulose derived nitrogen doped graphitic carbon material containing titanium dioxide

ABSTRACT

Nitrophenols (NPs) and their derivatives are highly toxic, mutagenic and bio-refractory pollutants commonly present in natural water resources and industrial wastewater. To remove NPs from water, N-doped graphitic carbon (NGC) and NGC adsorbent containing titanium dioxide (NGC–TiO₂) were synthesized by pyrolysis of microcrystalline cellulose and dopamine mixture, and the mixture along with TiO₂ at 500°C, respectively. NCG-TiO₂ was thoroughly characterized using various analytical techniques. NP adsorption on the NGC–TiO₂ adsorbent surface was studied by varying the pH, initial concentration of NP, and adsorbent dose. The results showed that the most efficient adsorption was achieved at pH 3. After 4 h sonication at pH 3, 80% 4-NP adsorption was achieved using NGC–TiO₂ compared to 74% with NGC adsorbent. The percentage removal of 4-NP was higher than 3-NP which was also higher than 2,4-DNP using NGC–TiO₂. 4-NP adsorption best fitted to the Langmuir isotherm plot with R² value of 0.9981 and adsorption capacity of 52.91 mg g⁻¹. The adsorption process of NP was found to follow a pseudo-second-order kinetic model. The rate constant value for the adsorption of 10⁻⁴ M 4-NP at pH 3 using 10 mg of NGC–TiO₂ adsorbent was found to be 3.76 × 10⁻⁵ g.mg⁻¹.min⁻¹

KEYWORDS:

• Adsorption
• microcrystalline cellulose
• N-doped graphitic carbon
• nitrophenols
• pyrolysis

Additional information

Funding

The authors would like to acknowledge to the financial support of this work provided by the National Science Foundation (Grant No. IIA 1457888) and the Arkansas EPSCoR Program, ASSET III.