Lancaster Environment Centre

Links

• Personal website
• RSC Environmental Chemistry Group
• Environmental Mineralogy Group

Biography

Imad obtained his PhD in Environmental Science from the University of Nottingham in 2006. His PhD research focused on the kinetic transfer of Cd²⁺ ions from aqueous solutions to the bulk of crystalline phases. Cd partitioning was studied in model systems (i.e., calcite and zeolites) under environmentally relevant conditions over a long reaction time (up to 200 days). A kinetic model was developed to describe the progressive transfer of Cd²⁺ to less reactive forms in calcite and zeolites. A particularly exciting part of this project was the use of synchrotron-based techniques (i.e., X-ray Absorption Spectroscopy; XAS) in studying the Cd intracrystalline diffusion and fixation mechanisms in the 3D lattice of Faujasite-type zeolites.

In 2007, Imad joined the Environmental Geosciences Research Group at the University of Leeds as a postdoc on a NERC funded project on the “Formation and transformation of ‘green rust’ and its influence on the mobility of trace elements in the environment”. In collaboration with Diamond Light Source, the mechanisms of green rust (layered Fe^II-Fe^III oxyhydroxide nanoparticles) formation and transformation were determined using a novel in situ approach combining time-resolved synchrotron-based Small- and Wide-Angle X-ray Scattering (SAXS/WAXS) techniques with highly controlled chemical synthesis and electrochemical monitoring of the reaction. Using this system the formation pathways of green rusts under different conditions in the absence or presence of key trace elements (e.g., Zn, Se, and U) were determined. In addition, reductive transformations of Se and U in the presence of green rust were studied using XAS techniques (i.e., EXAFS and XANES).

Current research

 In Sept 2009, Imad joined the Aquatic Chemistry Research Group at Lancaster University. He is currently working on a NERC funded project titled “Predicting metal speciation in freshwaters: resolving uncertainty using a multi-method approach”. The project aims to assess elemental speciation, and bioavailability using dynamic and in situ methods including Diffusive Gradients in Thin Films (DGT) and Donnan Membrane Technique (DMT). This project is led by Dr. John Hamilton-Taylor, Dr. Hao Zhang, and Prof. Bill Davison and in collaboration with Prof. Ed Tipping at CEH-Lancaster. Imad has a broad range of research interests in the aqueous chemistry, analytical environmental chemistry, geochemistry and biogeochemistry of soil, sedimentary, and aqueous environments. These interests are interdisciplinary in nature, integrating:

1. The influence of soil redox processes, organic matter, and microbial activity on the speciation and mobility of key trace elements (U, As, Se, Cr, Cu, Ni, Cd, Pb, and Zn).
2. Mineral dissolution, crystallization reactions, generation of colloidal phases, aggregation and precipitation processes.
3. The use of synchrotron- based techniques including EXAFS/XANES, SAXS, FTIR and time resolved in situ XRD in the identification of the possible mechanisms that limit the reactivity of trace elements in the environment.
4. The development of novel analytical methods that help understanding the cycling of redox sensitive elements and the effect of natural nanoparticles on the fate of these elements in the environment.