McLaughlan, RG, Hossain, SMG & Al-Mashaqbeh, OA 2015, 'Zinc sorption by permanganate treated pine chips', Journal of Environmental Chemical Engineering, vol. 3, no. 3, pp. 1539-1545.View/Download from: Publisher's site
© 2015 Elsevier Ltd. All rights reserved. The sorption equilibria and kinetics of zinc from aqueous solution on both untreated and permanganate treated pine chips were investigated. The sorption kinetics were best described by pseudo-second-order equation and the sorption isotherms were well fitted by a Langmuir model for both untreated and treated pine chips. Zinc sorption increased from 1.2 mg g -1 in untreated samples to 3.9 mg g -1 for the treated pine chips. Analysis shows that the carboxylic content increased after oxidative treatment of wood sorbents. This was responsible for the improved sorption of zinc onto the pine chips. The permanganate-wood reaction rate in batch experiments was biphasic first-order with an initial rate (0-25 min) and then a slower rate (25-807 min). The initial rates were approximately 3 times greater than the later stage rates. The reaction rates was also particle size dependent with the rate for 4.75 mm pine chips, 11-19% less than that of the 1.18 mm pine chips. Rate limiting mechanisms included intra-particle mechanism of MnO 4 - interaction with pine chips is complex and consisting of surface external mass transfer as well as intra-particle diffusion. Rate-limiting reactions in the column caused the shape of the breakthrough curve to exhibit tailing.
Hossain, S & McLaughlan, RG 2014, 'Effect of wood particle size on uptake and desorption study of chlorophenols by woody materials', Environmental Technology, vol. 35, no. 12, pp. 1484-1490.View/Download from: Publisher's site
The impact of particle size on biosorbent performance is not well researched. Batch tests found pine and hardwood (HW) had a chlorophenol (CP) uptake of 3.17.1 mg g-1 with an initial rapid uptake but equilibrium within 72 h. Pine particle size (0.64.75 mm) was relatively independent of surface area and equilibrium CP uptake. This was due to the elongate nature of the ground particles which had a length to width ratio of between 4:1 and 8:1 and a sieved particle size closely aligned with particle width rather than particle length. Intra-particle diffusion was a dominant sorption mechanism. Sorptiondesorption isotherms of CP on pine andHWcan be best described by the Freundlich equation. Desorption of CP showed greater hysteresis with increased hydrophobicity.
Hossain, S & McLaughlan, RG 2013, 'Kinetic investigations of oxidation of chlorophenols by permanganate', Journal of Environmental Chemistry and Ecotoxicology, vol. 5, no. 4, pp. 81-89.View/Download from: Publisher's site
The kinetics of oxidation of various chlorophenols such as 2-chlorophenol (2Â·CP), 3-chlorophenol (3-CP), 4-chlorophenol (4-CP), 2,4-dichlorophenol (2,4-DCP), 2,6-dichlorophenol (2,6-DCP) and 2,4,6-trichlorophenol (2,4,6-TCP) by potassium permanganate (0.8-3.2 mM) were studied in unÂ·buffered solution with ionic strength -0.02 M. Experimental results was indicated that the reaction of CPs with permanganate was of second-order overall (0.86 to 19.0 M-ls-1) and the reaction is first-order individually with respect to both permanganate and all chlorophenols (CPs) at an initial pH -7.0 and 22'C. The degradation rate of chlorophenols can be accelerated by increasing oxidant concentration. The reaction rates of 4-CP with permanganate did not show any significant change over pH 5.5 to 8.5 and ionic strength -0 to 0.2 M. The determined rate constants allowed us to predict the reaction rates of CPs with KMn04 during oxidative treatment of CPs at contaminated sites.
Hossain, S & McLaughlan, RG 2012, 'Sorption of chlorophenols from aqueous solution by granular activated carbon, filter coal, pine and hardwood', Environmental Technology, vol. 33, no. 16, pp. 1839-1846.View/Download from: Publisher's site
Wood and coal, as low-cost sorbents, have been evaluated as an altemative to commercial granular activated carbon (GAC) for chlorophenol removal. Kinetic experiments indicated that :filter coal had a significantly lower rate of uptake ("" I 0% of final uptake was achieved after three hours) than the other sorbents, owing to intra-particle diffusion limitations. The data fitted a pseudo-second-order model. Sorption capacity data showed that GAC had a high sorption capacity (294--467 mg g-l) compared with other sorbents (3.2-7.5 mg g-I). However, wood and coal had a greater sorption capacity per unit sUlface area than GAC. Sorption equilibrium data was best predicted using a Freundlich adsorption model. The sorption capacity for all sorbents was 2-chlorophenol < 4-chlorophenol < 2, 4-dichlorophenol, which correlates well with solute hydrophobicity, although the relative dillerences werc much less for coal than the other sorbents. The results showed that pine, hardwood and filter coal can be used as sorbent materials for the removal of chlorophenol from water; however, kinetic considerations may limit the application of filter coal.