فهرست مطالب مهران بیجاری

Photocatalytic processes using solar energy are one of the new chemical purification methods in the purification of colored organic pollutants, attracting much attention. Graphite carbon nitride photocatalyst (g-C3N4) was synthesized using the thermal polymerization method and using (single or combined) melamine, thiourea, and ammonium chloride precursors. Synthesized photocatalysts based on g-C3N4 were analyzed to investigate their structure, morphology, and properties using XRD, FT-IR, SEM, EDX, BET, PL, and DRS analyses and to degrade the cationic dye Rhodamine B (RhB) used. The results of the experiments showed that the graphite carbon nitride synthesized with the combined precursor of melamine, thiourea, and ammonium chloride (MTA) with a dose of 0.2 g/l and a color concentration of 50 mg/l has the highest performance on the degradation of RhB color and after 2 hours, caused 100% decolorization of the dye solution. Also, the photocatalytic efficiency of MTA in the degradation of RhB dye was almost constant in five consecutive cycles. In addition, according to the results of the trapping experiments, the active species of superoxide radical (•O2-) was the dominant species for the degradation process of RhB. Hence, MTA can be considered an efficient catalyst due to its advantages, such as one-step synthesis, effective photocatalytic performance, and reusability.

Reactive dyes are the most commonly used dyes in textile industry. During the dyeing process about 60 to 70 percent of consumer dye is fixed on the fibers. So about 10-15 % of consumed reactive dyes enters into the wastewater and causes environmental problems. The aim of this study was to remove Reactive Blue 19 and Reactive Red 198 dyes using activated carbon made from waste of tree pruning grapes in a batch system.

In this study, activated carbon were synthesized with phosphoric acid in a ratio of 1: 2 at 400 C °. Also the optimum conditions for maximum adsorption of reactive Blue 19 and Red 198 dyes was determined (pH=2, adsorption dose= 0.05 g/l, dye concentration = 300 mg/l, temperature = 60°C, solution volume = 200 mL and contact time= 120 min).

Batch adsorption results showed that activated carbon sample with a surface area 1950 m2/g and total pore volume 1.588 cm3/g and 51 percent pore size distribution in the range of micro-hole with the maximum adsorption capacity 1154 mg/g for Reactive Blue19 and 431 mg/g for Reactive Red 198 (In optimum condition) has great potential for the removal of dyes. Experimental data for Reactive Blue 19 are more compliance with Freundlich model and experimental data for Reactive Red 198 are more compliance with Langmuir model. Adsorption of dyes also be followed pseudo-second-order kinetic model.

The study showed activated carbon produced from annual pruning vineyards waste has high potential in the treatment of textile wastewater

Mesoporous activated carbon production from lignocellulose waste for removing reactive dyes Blue 19 and Blue 21 from aqueous solution Introduction. Reactive dyes have been increasing in textile industries for dyeing natural and synthetic fibers. Discharge of dye- bearing waste-water makes an adverse effect on aquatic environment because the dyes give water undesirable color. The major environmental and health problems associated with water pollution caused by the discharge of untreated textile effluent are due to disorders in the aquatic environment because of use of toxic chemicals. The aim of this study was to investigate the adsorption potential of as-produced activated carbon from grape wood residue (Vitis Vinifera) in order to remove Reactive Blue 19 (RB19) and Reactive Blue 21 (RB21) dyes from aqueous solution. Activated carbon is the most common adsorbent for the removal of many dyes.Activated carbons are made from various agricultural wastes by physical and chemical activation. The preparation of activated carbon from agricultural waste could increase economic return and also provides an excellent method for the solid waste disposal thereby reduce pollution. The adsorbates in this study included three reactive dyes, Reactive Red 23 (RR23), Reactive Blue 19 and Reactive Blue 21. All dyes were commercial grade and employed without further purification. The activated carbon was synthesized from grape wood biomass by activation of phosphoric acid (H3PO4) with impragnation ratios of 1:1 1:2,1:3, 1:4. The FTIR, BET, and SEM techniques were used to characterize the as-prepared carbon materials. In addition, dye adsorption experiments were carried out, which measurements are taken for all of the samples under in the same condition, at pH of 2, adsorbent dose of 0.01 g/l, initial dye concentration of 250 mg/l, sworking volume of 100 ml, and contact time of 120 min. The results showed that the carbon sample activated under imprenation ratio of 1:4 and temperature of 600oC, that obtained a special surface area of 1850 m2/g, and total pore volume of 2.40 cm3/g, and pore size distribution of mesoporous at 86%, had maximum adsorption capacity of 1932 and 908 mg/g for RB19 and RB21 dyes, respectively. The adsorption behaviors of three reactive dyes (Reactive Blue 19 23, Reactive Blue 21) onto this biomass activated carbon were investigated in batch systems. The experimental data were analysed by the Langmuir, Freundlich and Sips models of adsorption. Equilibrium data of dyse fitted well with the Sips model. The rates of adsorption were found to conform to the pseudo-second-order kinetics with good correlation. The equilibrium adsorption capacity of the Activated carbon was determined with the Langmuir equation found to be 1914 mg/g for Reactive Blue 19 and 1195 mg/g for Reactive Blue 21. This study showed that activated carbon produced from annual pruning vineyards waste has a high potential in the treatment of textile wastewater. Also results indicate that Activated carbon from grape wood could be employed as low-cost alternative to commercial activated carbon in wastewater treatment for the removal of acid dyes. Keywords: Activated carbon, lignocellulose waste, Grape wood, Blue 19, Blue 21

Reactive dyes are the newest dyes in textile industry. They may cause environmental problems. The aim of this study was to remove Reactive Black 5 (RB5) in aqueous solutions with activated carbon that was made from grape wood.
The activated carbon was synthesized by potassium carbonate with impragnation ratios of 1:0.25 at different temperatures (600,650,700,750,800,850,900)°C. Experiments on dye adsorption were done under the same conditions including pH of 2, adsorbent dose of 0.025 g/L, initial dye concentration of 250 mg/L, volume of 100 mL, and contact time of 120 min. Then, the absorption RB5 in a bathc mode was done using the optimized activated carbon. The trends of pH, absorbent dose, initial concentration, temperature, retention time, parametrs were studied. The BET and SEM techniques were used to characterize the activated carboon. Finally, the equilibrium, synthetic and thermodynamic studies were done for RB5.
The results showed that the activated carbon sample that was synthesized under the imprenation ratio of 1:0.25 and temperature of 900 oC had a surface area 1670 m2/g. Moreover, the total pore volume was 1.134 cm3/g and 68% of the total pore size were within mesoporous zone. The highest adsorption capacity was observed at the optimum condition. The optimum condition with the maximum adsorption capacity for RB5 was pH of 2, adsorbent dose of 0.035 g/L and temperature 45 °C. According to the equilibrium test results RB5 followed the Freundlich model. of the kinetic adsorption results showed that RB5 showed a pseudo-second-order kinetic model. According to the thermodynamic studies, it seems that RB5 absorption process was an endothermic, non-spontaneous and physical sorption process.
The study showed that the produced-activated carbon from grape wood had a great potentioal for removing RB5 from aqueous solutions.