B. Petrova

Adsorption of naphthalene from aqueous solution on activated carbons obtained from bean pods

The preparation of activated carbons from bean pods waste by chemical (K(2)CO(3)) and physical (water vapor) activation was investigated. The carbon prepared by chemical activation presented a more developed porous structure (surface area 1580 m(2) g(-1) and pore volume 0.809 cm(3) g(-1)) than the one obtained by water vapor activation (258 m(2) g(-1) and 0.206 cm(3) g(-1)). These carbons were explored as adsorbents for the adsorption of naphthalene from water solutions at low concentration and room temperature and their properties are compared with those of commercial activated carbons. Naphthalene adsorption on the carbons obtained from agricultural waste was stronger than that of carbon adsorbents reported in the literature. This seems to be due to the presence of large amounts of basic groups on the bean-pod-based carbons. The adsorption capacity evaluated from Freundlich equation was found to depend on both the textural and chemical properties of the carbons. Naphthalene uptake on biomass-derived carbons was 300 and 85 mg g(-1) for the carbon prepared by chemical and physical activation, respectively. Moreover, when the uptake is normalized per unit area of adsorbent, the least porous carbon displays enhanced naphthalene removal. The results suggest an important role of the carbon composition including mineral matter in naphthalene retention. This issue remains under investigation.

Removal of detergents from water by adsorption on activated carbons obtained from various precursors

AbstractThe adsorption of detergents—sulfonic and phenolic compounds—from aqueous solutions by activated carbons (AC), obtained on the base of different precursors, was studied. The carbon adsorbents used were prepared by water vapor pyrolysis of different raw materials: peach stones, olive stones, natural asphaltite, mixtures from coal tar pitch, and furfural. It was established that all the samples of ACs have close values of high adsorption capacities toward the studied detergents. Some factors affecting the adsorption process—the time of treatment and the amount of the adsorbent—were investigated. It was established that the amount of adsorbent has no significant influence on the adsorption process.

Thermochemical Conversion of Bean Pods to Carbon Materials and Gas

The preparation of activated carbons from bean pods by chemical (K 2 C0 3 ) and physical (water vapor) activation was investigated. The carbon prepared by chemical activation presented more developed porous structure than one obtained by water vapor activation. Carbon adsorbent with very low ash content and developed micropore structure is obtained by thermochemical treatment with conc .H 2 S0 4 of liquid products from carbonization of bean pods and activation with water vapour. K e y w o r d s : bean pods, K 2 C 0 3 activation, water vapor activation