Guava seed as an adsorbent and as a precursor of carbon for the adsorption of acid dyes

The guava seed (SEGUVE) was characterized by ultimate and proximate analysis. In SEGUVE the principal thermal effect occurred at 363 °C and this can be attributed to the cellulose degradation, which was the main component (∼61%). The guava seed has an acidic character with a high content of bulk functional groups (CO) and these characteristics were affected by carbonization. Two samples of carbon were prepared from the seeds at 600 and 1000 °C without chemical activation. Adsorption of eight acid dyes belonging to the monoazo and anthraquinone class was studied at 25 °C. The non-carbonized SEGUVE adsorbed the acid dyes more efficiently than SEGUVE-C600 and SEGUVE-C1000 although the specific surface of the raw material SEGUVE was low.