This study highlights the importance of a cheap bio waste; Pine Nut Shell (PNS), from which a carbon is synthesized that can efficiently remove toxic phthalates from an aqueous system. PNS derived carbon shows high affinity toward phthalates in descending order along with adsorption capacity i.e., dibutyl phthalate (DBP) 5.65mg/g>diallyl phthalate (DAP) 3.64mg/g>diethyl phthalate (DEP) and 2.87mg/g>dimethyl phthalate (DMP) 2.48mg/g. Different characterization techniques such as FTIR, elemental analysis, point of zero electric charge (PZC), SEM, EDX and BET were employed to investigate the binding sites and surface area of the adsorbent. Adsorption experiments were performed both in batch and column modes. Equilibrium studies showed that the Langmuir isotherm fits best to experimental data. Kinetically, adsorption phenomena obeyed pseudo second order. Furthermore, thermodynamic results expressed the exothermic nature of adsorption on the basis of negative value of enthalpy change. Column sorption method was also adapted to check the feasibility of the adsorption process through the investigation of flow rate, breakthrough curve and pre-concentration factor which is found to be 13 for DMP and DEP and 16 for DAP and DBP. Methanol was found to be best solvent for the recovery of phthalates. Application in real water samples also showed good efficiency of PNS derived carbon for the removal of phthalates
Distribution and risk assessment of eight priority polycyclic aromatic hydrocarbons (PAHs) contents have been examined in different varieties of vegetables grown in Pakistan. The results showed that the total PAH contents were higher for root vegetables like potato and carrot (~13 μg/kg) and relatively lower for turnip (10.9 μg/kg), respectively while for the fruit vegetables, all the peels were found to be more contaminated than cores. The ratio of total PAH concentrations in peels with respect to those of cores is found to be 1.45, 1.26, 1.31, 1.44, 1.40, and 1.36 for potato, turnip, carrot, eggplant, cucumber, and bitter gourd, respectively. For leafy vegetables, cabbage showed maximum PAH (11.6 μg/kg) as compared to the cores of fruit vegetables. Among individual PAH congeners, anthracene showed higher levels in all vegetables. For benzo(a)anthracene, maximum concentration (3.44 ± 2.10 μg/kg) was encountered in turnip cores. Highest benzo(e)pyrene concentration was found in potato (3.19 ± 1.67 μg/kg) followed by turnip (2.74 ± 1.22 μg/kg). Benzo(b)fluoranthene and benzo(k)fluoranthene showed relatively lower levels in all samples studied. All the concentrations of PAHs are presented on a fresh weight basis. The results of human exposure of PAH by consumption of these vegetables showed that cumulative dietary exposure of Pakistani population to PAHs from vegetables ranges from 0.25 μg/p/d to 1.16 μg/p/d.