Hasan Sayğılı

Uptake of anionic and cationic dyes by highly effective porous carbon adsorber based on industrial processing residues

ABSTRACT In this work, we investigated the performance of porous carbon prepared from carob (Ceratonia siliqua L.) processing residues at optimized conditions for the removal of the Basic Green 4 (BG4) and Direct Red 28 (DR28) dyes from aqueous solutions. The influence of several parameters such as adsorbent dose, initial dye concentration, contact time and temperature was evaluated in batch adsorption experiments. Maximum adsorption capacities were observed as 769 mg g−1 and 323 mg g−1 for BG4 and DR28, respectively. These results suggest that BG4 and DR28 could be removed using a novel porous carbon from carob processing residues.

Behavior of mesoporous activated carbon used as a remover in Congo red adsorption process

The adsorption characteristics of Congo red (CR) dye on activated carbon produced under optimized conditions from tomato paste waste were evaluated. The effects of adsorbent dose, initial dye concentration, contact time, ionic strength and solution temperature on adsorption were investigated. Adsorption kinetic was better described by the pseudo-first order model. Results of the intra-particle diffusion model show that the pore diffusion is not the only rate-limiting step. Adsorption isotherm was well defined by the Langmuir isotherm. The maximum adsorption capacity of the activated carbon was 435 mg g-1 at 328 K. The dimensionless separation factor RL revealed the favorable nature of the isotherm of the activated carbon-dye system. Adsorption energy was found to be 4.20-4.55 kJ mol-1 indicating that the mechanism of adsorption is physical in nature. Thermodynamic studies showed that CR adsorption onto activated carbon was feasible, spontaneous and endothermic. Desorption of the used activated carbon was studied using ethanol as solvent and desorption efficiency of 56.4% was obtained after five cycles. The findings indicated that the activated carbon is a very effective and low-cost adsorbent for removal of CR dye from aqueous solutions.

Surface modification of black tea waste using bleaching technique for enhanced biosorption of Methylene blue in aqueous environment

ABSTRACT In the current study, the bleaching technique with sodium hypochlorite (NaOCl) was used to modify black tea waste (BTW) for enhancing its biosorption performance of Methylene blue (MB) dye. Fourier transform infrared (FT-IR), scanning electron microscopy (SEM), (thermogravimetric-differential thermal analysis) TG/DTA, X-ray diffraction (XRD), Brunauer–Emmett–Teller (BET) analysis and surface acidity and pHpzc measurements were employed to determine the textural structure and surface chemistry of the raw and NaOCl-modified BTW. The results indicate that after using bleaching modification, the MB biosorption capacity of BTW was enhanced approximately threefold. Maximum biosorption capacities were found as 125 mg g−1 for BTW and 416.67 mg g−1 for bleached black tea waste (BBTW). GRAPHICAL ABSTRACT