Adsorption studies of p-Nitrophenol from Model aqueous solutions using Raw and Quaternised thorn melon (Cucumis metuliferus) peels

Phenolic compounds are injurious to human and animal health, for instance PNP is an eye irritant and its ingestion or inhalation brings about vomiting, sleepiness, headaches and ataxia. Interaction of PNP with blood leads to confusion, cyanosis and unconsciousness. Conventional water treatment methods for example; use of activated carbons involve high production cost hence not attractive to many needy people. It’s important to explore on cheaper alternatives for removing PNP from drinking water. The current inquiry deals with the utilization of thorn melon (Cucumis metuliferus) peels in their raw and modified forms as adsorbents for PNP. Raw thorn melon peels were modified using a quaternary ammonium salt and then applied for the uptake of p-Nitrophenol (PNP) from aqueous media. The influence of experimental parameters: concentration, contact time, pH, sorbent dose, temperature and initial concentration were investigated. The adsorbent materials were characterized using FTIR. The adsorption behavior of the PNP was studied using Langmuir and Freundlich isotherm models. The physical sorption load was 12.79 and 16.31 mg/g for raw and quaternised thorn melon peels respectively from Langmuir adsorption equation. Uptake of PNP on adsorbent was indicated to rise with decreased initial concentration and lowering pH to a value of 3. This study showed that thorn melon peels are friendly to the environment, cheap biosorbents and useful which can be applied for the uptake of PNP from drinking water especially in quaternised form.