Efficiency of Multi-Walled Carbon Nanotubes in TPH Adsorptionin Aqueous Solution (Case study: Naphthalene)

Oil pollution is a type of organic water pollution. The hydrocarbons constitute most of the petroleum composition. Most of the early aromatic hydrocarbons are naphthalene with two benzene ring which cause anemia and damage the retina. It is also toxic to plants and aquatic environment. The removal of this compound from water by multi-walled carbon nanotubes is reviewed in this study.
This experimental study was done in a batch system to investigate the effects of variations factors such as contact time, naphthalene concentration and dose of nanotubes on removal of naphthalene. In this study, naphthalene concentration was determined during various steps using UV-vis spectrophotometer at 254 nm.
Findings: Maximum surface adsorption of naphthalene onto multi-walledcarbon nanotubes was 33.3 mg/gr and the maximum adsorption occurred at acidic pH (pH =3). And the appropriate time for reaching the maximum adsorption rate of naphthalene and equalization state was 90 min. By increasing the adsorbent dose from 0.2 to 0.3 gr / l, removal efficiency of naphthalene solution with 10 mg/l initial concentration increased from 97% to 99.99%. By increasing naphthalene initial concentration from 3 to 10 mg/l, the removal efficiency increased from 73.33% to 99.99 % at pH=3 after 90 min. Adsorption mechanism followed pseudo first-order kinetics (R2=0.96).
Discussion and This adsorbent could be effective for removal of naphtalene due to its small size, large surface area , crystal shape and exclusive network arrangement and consequently very high reactivity and noticeable performance of multi-walled carbon nanotubes as adsorbent in removal of organic pollutants from aqueous solution.