A novel efficient adsorbent, alkali-pretreated Paeonia ostii seed coats (AP-PSC), was investigated for the removal of methylene blue (MB) dye from solution. Orthogonal array design was applied to optimize the process parameters viz. alkali concentration, liquid-solid ratio (LSR) and pretreatment time. The results revealed that the optimal pretreatment conditions were at 0.8% (w/w) NaOH with LSR of 0.35 L g–1 treating for 50 min. Equilibrium and kinetic studies indicated that Langmuir isotherm and Pseudo-second-order models described the experimental data well. The maximum adsorption capability was of 368.2 mg g–1 for MB at 25°C. Thermodynamic parameters suggested that the AP-PSC adsorption process was physical, endothermic and spontaneous. Furthermore, the adsorption process was influenced by several interactive mechanisms, including ion-exchange, as well as Van der Waals forces and hydrogen bonds that occur concomitantly. It was concluded that AP-PSC may be potential as an efficient adsorbent to remove MB from solution.
2
Dostęp do pełnego tekstu na zewnętrznej witrynie WWW
The oxidative catalytic degradation of the cationic dye methylene blue (MB) with NaOCl in aqueous solutions was studied using individual and iron modified Ni- and Co-oxide systems as catalysts. The adsorption extent and the contribution of the uncatalyzed oxidation on the overall degree of MB were determined. The results indicate that methylene blue-a representative of a class of dyestuffs resistant to biodegradation-could be successfully decolorized and degraded using nickel and cobalt oxide catalysts at room temperature. The highest catalytic activity manifests in the Co-oxide system which is consistent with the adsorption data. The oxidative degradation reaction proceeds via first-order kinetics. Temperature has a relatively small effect on the methylene blue degradation kinetics. The results obtained reveal that the catalysts investigated are suitable for oxidative destruction of methytlene blue dye in wastewaters. [...]
3
Dostęp do pełnego tekstu na zewnętrznej witrynie WWW
This study illustrates the preparation of activated carbon (AC) from Corn Cob (CC) via microwave assisted K2CO3&enspactivation. The effect of operational parameters including chemical impregnation ratio (0.25-1.25), microwave power (90 – 800 W) and irradiation time (1 – 9 min) on the carbon yield and adsorption capability of derived Corn Cob Activated Carbon (CCAC) were investigated. The results indicated that the optimum conditions were as follows: microwave power of 600W, microwave radiation time of 5 min and the impregnation ratio of K2CO3&enspwas 0.75 g/g. The optimum conditions resulted in CCAC with a maximum adsorption capacity of 275.32 mg/g for MB and carbon yield of 27.09%. The BET surface area, Langmuir surface area and total pore volume were determined to be 765 m2/g, 834 m2/g and 0.43 cm3/g, respectively.
JavaScript jest wyłączony w Twojej przeglądarce internetowej. Włącz go, a następnie odśwież stronę, aby móc w pełni z niej korzystać.