Document Type : Original Article
Department of Chemical Engineering, College of Engineering, University of Al-Qadisiyah , AL-Qadisiyah, Iraq
This research includes the effect of activated carbon, the flow rate of the adsorption system, the weight of activated carbon, and contact time between the material to be adsorbed and activated carbon in the treatment of wastewater contaminated with the active substances of methylene blue MBAS from petroleum and petrochemical plants using the adsorption process in a system with a fixed bed and continuous flow. The adsorption process was studied in the presence of two types of activated carbon prepared from local materials available in abundance and at very low prices (wheat husks peganum). The constant bed system was used to conduct the MBAS absorption process on the prepared activated carbon and study the effect of the flow rate, the weight of the activated carbon, and the contact time during the experiments. Activated carbon was prepared by burning (wheat husks) at a temperature of 275 °C for 90 min under the nitrogen gas flow in (4) liters/hour. The same steps were performed for the peganum. The method of chemical activation was also used with phosphoric acid (wheat husks, peganum) and (4) molar solution and leaving the raw materials for (24) hours in the solution for effective activation. They were thoroughly washed with water to enter the oven and incinerated at a temperature of 700°C for wheat husks and 500° C for peganum. SEM’s two BET assays investigated the resulting active carbon’s surface area and surface morphology. The surface area values were (775) m2/g for the activated carbon produced from the peganum plant and (615) m2 / g for the activated carbon produced from wheat husks for both types of carbon. Electron microscopy properties show that activated carbon prepared from peganum has a higher surface porosity than that prepared from wheat husks when using the same activated agent. The isotherms and adsorption kinetics of the dye was investigated at temperatures (30-60)°C for a concentration range of (50 - 250) mg/L.The study results showed that the maximum removal capacity of MBAS using activated carbon prepared from peganum is greater than that prepared from wheat husks. The results showed the first-order rapid increase in the adsorption rate, and the second-order pseudo-model represented the data well. The adsorption system was selected by selecting the best contact time between the material to be adsorbed and the prepared activated carbon, the best solution flow rate, and the activated carbon’s best weight. The results indicated that the best absorption time was (2) hours, the best weight of activated carbon was 10 grams, and the best flow rate was 0.1 liter/hour.