Remediation of phenol-contaminated water by adsorption using poly(methyl methacrylate) (PMMA)

Recently polymeric adsorbents have been emerging as highly effective alternatives to activated carbons for pollutant removal from industrial effluents. Poly(methyl methacrylate) (PMMA), polymerized using the atom transfer radical polymerization (ATRP) technique has been investigated for its feasibility to remove phenol from aqueous solution. Adsorption equilibrium and kinetic investigations were undertaken to evaluate the effect of contact time, initial concentration (10-90 mg/L), and temperature (25-55 degrees C). Phenol uptake was found to increase with increase in initial concentration and agitation time. The adsorption kinetics were found to follow the pseudo-second-order kinetic model. The intra-particle diffusion analysis indicated that film diffusion may be the rate controlling step in the removal process. Experimental equilibrium data were fitted to five different isotherm models namely Langmuir, Freundlich, Dubinin-Radushkevich, Temkin and Redlich-Peterson by non-linear least square regression and their goodness-of-fit evaluated in terms of mean relative error (MRE) and standard error of estimate (SEE). The adsorption equilibrium data were best represented by Freundlich and Redlich-Peterson isotherms. Thermodynamic parameters such as Delta G degrees and Delta H degrees indicated that the sorption process is exothermic and spontaneous in nature and that higher ambient temperature results in more favourable adsorption. (C) 2011 Elsevier B.V. All rights reserved.

Care Leavers’ Experiences of Transition and Turning Points: Findings from a Biographical Narrative Study

This paper reports on the findings of a PhD research project that set out to explore how young people leaving out of home care experienced and made sense of their transition to adulthood. Using the Biographical Narrative Interpretative Method, in-depth accounts were collected and analysed for eight care leavers. The data suggest that in addition to care leavers living their lives as a series of biographical events, their ‘care career’, they also experience changes in the way they make sense of their lives which form a ‘subjective pathway’. Influenced by the literature on resilience, the research had anticipated that ‘turning point’ events would play a significant role in the young people’s subjective pathways. But the findings show a more gradual, phased shifting of subjectivity. It is suggested that legislation, policy, services and care practices need to facilitate this more drawn out ‘subjective pathway’. Attachment, resilience and humanistic social psychology are proposed as useful theoretical underpinnings for that work