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​ أقيمت صباح أمس الثلاثاء 23-4-1437هـ   الندوة العلمية الأولى ضمن فعاليات ندوات علمية لقسم الكيمياء للفصل الدراسى الثانى 1437، 

قدمها الدكتور / ​فؤاد عارف باير عبابنه​  عضو هيئة التدريس بقسم الكيمياء  وقد حضرها السادة  أعضاء القسم ولاقت استحسان الحضور.

وقد اوضحت  اللجنة العلمية بقسم الكيمياء أن هذه الندوات  العلمية مفتوحة لجميع منسوبي الجامعة من أعضاء هيئة تدريس وطلاب، هادفة منها التعريف بمجالات القسم البحثية وجذب الطلاب للمشاركة  محققة أهداف الجامعة في دعم العلوم و التقنية والابتكار، وقامت اللجنة الثقافية بتوثيق المحاضرة لضمها لأنشطة القسم.

Abstract :

The mercury cycle in the environment is very complex and different transformations occur simultaneously under the same conditions. Examples include the methylation of Hg and demethylation of MeHg, photooxidation and photoreduction, evasion and deposition. As a result, different mechanisms are involved in this cycle. The general purpose of this work is to provide some information and knowledge about these processes and the environmental parameters that affect these reactions.

Iron species are commonly present in freshwaters, and Fe(III) complexes with organic carboxylates are photosensitive compounds. When exposed to radiation of suitable wavelength, they undergo ligand-to-metal charge transfer, resulting in an excited state which decomposes with formation of Fe(II) and highly reducing organic radicals. These radicals play an important role in the reduction of Hg(II).  Knowing that the carboxylate group is one of the major functional groups in humic materials, ferrioxalate is therefore a model for the role of iron-humic complexes in the photoreduction of mercuric ion.

In addition to the photochemical role of DOC, complexation reaction with both Hg and MeHg are very important in the aquatic environment and play a key role in the speciation of Hg(II), and this, in turn, affects the bioavailability and mobility of different Hg species. In this research area, we investigate the kinetics of Hg-DOC and MeHg-DOC binding in different size fractions with some emphasis on the effects of pH and concentration ratio of Hg to DOC.