| Popis: |
Comparative adsorption study of some toxic metals (Ni, Fe, Cu, Cd, and Pb) from battery industrial effluent by purified and polyethylene glycol-modified carbon nanotubes (CNTs) is reported. The as-prepared CNTs via chemical vapour deposition method (A-CNTs), its acid purified form (P-CNTs), and polyethylene glycol functionalized form (PEG-CNTs) were characterized by HRTEM, BET, HRSEM, FTIR and XRD. The HRSEM and HRTEM micrograph revealed the formation of multi-walled tubular network structures of different inner and outer diameter. The BET study of PEG-CNTs and purified CNTs showed surface areas of 970.81 m2/g and 781.88 m2/g, respectively. The nanomaterials batch adsorption effect of various parameters such as contact time, nano-adsorbent dosage and temperature was conducted. The optimum equilibrium to achieve maximum removal of Cd (83.41 %), Ni (92.79 %), Fe (95.93%), Pb (97.16 %) Cu (99.9 9%) using PEG-CNTs was 90 min of contact time, 0.3 g of nano-adsorbent dosage and 60 oC temperature. While the maximum percentage removal efficiencies accomplished using P-CNTs under the same applied conditions were Cd (78.64 %), Ni (76.12 %), Fe (92.87 %), Pb (90.7 2%) Cu (99.09 %). PEG-CNTs was seen as more effective than P-CNTs. Adsorption data of Ni on P-CNTs followed Langmuir isotherm while the adsorption equilibrium model (Freundlich isotherm) of Ni, Fe, Cu and Pb on PEG-CNTs were fitted well. However, in both cases, the sorption kinetic study followed the pseudo-second-order model. The thermodynamics showed that the removal of toxic metals from battery wastewater was spontaneous and endothermic irrespective of the nano-adsorbents. The study found that surface modification of CNTs by polyethylene glycol adequately improved the nanotubes, thus leading to relatively adsorption capacities of heavy metals from industrial battery effluent. |
