The use of polyethyleneglycolmethacrylate-co-vinylimidazole (PEGMA-co-VI) microspheres for the removal of nickel(II) and chromium(VI) ions.

The polyethyleneglycolmethacrylate-co-vinylimidazole (PEGMA-VI) copolymers, that can be used in heavy metal removal applications, were synthesized and characterized; and their use as sorbents in heavy metal removal was investigated. It was determined that the ligand vinylimidazole was successfully inserted into the polymer structure. Then, chromium (Cr(VI)) and nickel (Ni(II)) ions were used as model species to investigate the usability of the obtained microspheres in heavy metal removal. The effects of pH of the adsorption medium, initial concentration of the metal ions and VI content of PEGMA-VI microspheres were investigated as the effective parameters on the adsorption capacities of the microspheres. The adsorption rate of the microspheres was also investigated for determination of the optimum adsorption time which is the required time for maximum adsorption capacity. The adsorption capacities under optimum conditions were also determined. The order of adsorption affinities of PEGMA-VI microspheres with respect to the used metals was determined by competitive adsorption studies. According to the obtained results, the highest adsorption affinity of the PEGMA-VI microspheres was towards Cr(VI) ions, the adsorption affinity was less for Ni(II) and the least affinity was towards Cu(II) ions. The adsorption-desorption studies showed that the microspheres were reusable without a significant decrease in the ion adsorption capacities

Preparation and characterization of polyethyleneglycolmethacrylate (PEGMA)-co-vinylimidazole (VI) microspheres to use in heavy metal removal.

Polyethyleneglycolmethacrylate (PEGMA) and vinylimidazole (VI) were used in order to obtain microspheres of PEGMA-VI copolymers that can be used in heavy metal removal applications. The obtained copolymers were characterized and their use as sorbents in heavy metal removal was investigated. In the first part of the study, PEGMA-VI microspheres were prepared by suspension polymerization method. The obtained swellable microspheres with 10-50 microm average diameter did not have permanent porosity according to the morphological and physicochemical determinations. The sizes of microspheres became smaller with increasing VI and cross-linker ethyleneglycoldimethacrylate (EGDMA) contents and increasing agitation rate. The VI content, EGDMA ratio, pH and ionic strength were determined as the effective parameters on the swelling behavior of PEGMA-VI microspheres. In the second part of the study, Cu(II) ions were used as a model species in order to investigate the usability of the obtained PEGMA-VI microspheres in heavy metal removal. Adsorption capacities under optimum conditions were determined. The Cu(II) ion adsorption capacity increased by increasing the initial Cu(II) ion concentration, and it reached the maximum value (i.e., 30 mg Cu(II)/g PEGMA-VI microspheres) at 400 mg Cu(II)/L initial Cu(II) ion concentration under the determined optimum conditions. Microspheres were found to be reusable after desorption for several times

Wound Dressings: A Comprehensive Review

This comprehensive review covers the advantage and limitations of some dressing materials and the current knowledge on wound dressings and emerging technologies to achieve proper wound healing.Traditional and modern dressings are helpful in the wound healing process; however, they cannot substitute lost tissue. Human skin equivalents have been developed conceptually to fill this void as they do not only facilitate wound healing but also may replace lost tissue. Several studies have shown that the addition of mesenchymal stem cells, such as in human placenta, has promising results in wound healing.A wound is defined as a disruption in the continuity of the skin or mucosa due to physical or thermal damage, or an underlying medical condition. Wound healing is a complex, dynamic, and multistep process which occurs after skin damage leading to tissue repair. Although the skin normally undergoes repair after a disruption, the healing process can be affected in different conditions such as diabetes mellitus, infections, venous/arterial insufficiency, among others. To enhance healing, a wide range of wound dressings are available; however, a thorough wound assessment (e.g., wound type, size, depth, or color) is required to choose the appropriate dressing. The emergence of new dressings has brought a new perspective of wound healing, but there is no superior product yet to treat acute and/or chronic wounds. Therefore, wound dressing research studies need to be carried out in order to help improve wound healing