Activated carbons with different textural and chemical surface characteristics were synthesized from waste biomass and low rank coals, and furthermore used as a host matrix for cobalt species, varying the preparation and modification methods. The obtained activated carbons and modified samples were characterized by complex of various physicochemical methods, such as: low temperature physisorption of nitrogen, XRD, EPR, XPS, UV–Vis and TPR with hydrogen. Boehm method was applied for qualitative and quantitative determination of oxygen-containing groups on the carbon surface before and after cobalt deposition. The catalytic properties of cobalt modifications were tested in methanol decomposition. The dominant effect of activated carbon texture over the surface chemistry on the state and catalytic behavior of cobalt species was discussed.Financial support from Bulgarian Academy of Sciences and Bulgarian Ministry of Education (Projects DFNI-Е01/7/2012 and DFNI-E02/2/2014) is gratefully acknowledged.Peer reviewe

Adsorption of mercury ions on activated carbon, prepared from polymer waste product, polyolefin wax (POW), was studied. The structure and surface properties of the sample are characterized by different methods—N₂ adsorption, IR spectroscopy, determination of surface oxygen groups. Adsorption studies of mercury(II) from aqueous solution on synthesized activated carbon are investigated under various conditions—agitation time, metal ion concentration, adsorbent quantity, pH. It was established that the adsorption follows both Langmuir and Freundlich isotherms. The activated carbon obtained from POW demonstrates high adsorption capacity toward mercury ions (196.1 mg/g). The results show that Hg²⁺ removal from water solutions increases with the increase of pH from 2 to 5, and slightly decreases at pH > 6.