Process Engineering

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Browsing Process Engineering by Subject "activated carbon"

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    Activated Carbon Preparation and Characterization from Flax Straw for Removal of Pb (II) Ions from Aqueous Solution and Industrial Wastewater
    (Addis Ababa University, 2021-09) Tayto, Mindahun; Shegaw, Ahmed (PhD)
    There are different modern technologies to remove heavy metals from industrial effluent. However, applying these modern technologies is impossible in all situations. Hence, investigating alternative technologies like adsorption by AC for such kinds of problem is very important. Considering this, the aim of this study was to prepare AC from flax straw and investigate its potential for the removal of Pb (II) ions from aqueous solution and paint industry wastewater. AC was prepared by chemical activation method using H3PO4 as activating agent. The effects of activation time, activation temperature and activating agent concentration on yield and iodine number were studied by using RSM. The effects of initial Pb (II) ion concentration, adsorbent dose, contact time and pH on removal efficiency were studied by using synthetic wastewater prepared from lead nitrate on a batch mode. The collected wastewater sample was characterized before and after treatment according to APHA methods. AC was characterized and results showed that the flax straw AC had 8.04% of moisture, 6.04% of ash, 18.615% of volatile matter, 79.421% of fixed carbon, 459.807 mg/g of iodine number and surface area of 489.455 m2/g. Physico-chemical characteristics revealed that raw wastewater had a concentration of 3.95 mg/L Pb (II), 158.52 mg/L BOD5, 2482 mg/L COD, and 652.667 mg/L TSS. The highest removal efficiencies of Pb (II) metal ion which was achieved from aqueous solution and paint wastewater were found to be 95.16% and 78.73%, respectively. The experimental data are fitted with pseudo-second order model and adsorption of Pb (II) on flax straw AC fits the model of Langmuir very well. The results suggested that flax straw AC can be used as adsorbent to remove Pb (II) ion from paint industry wastewater.
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    Decolorization of Cane Syrup by Activated Carbon Produced From Peanut Shell
    (Addis Ababa University, 2019-06) Askal, Haile; Shimelis, Kebede (PhD)
    Sugar colourants are water soluble compounds present in sugar process products and the most impurities in sugar industry. Syrup decolorization can be achieved by sulphitation process. However, at the same time the formation of fine precipitate of CaSO4 become difficult to eliminate trace of SO2 in final sugar. The aims of this research were to produce activated carbon from peanut shell using KOH as an activating agent for syrup decolorization with lower color and lower residual sulfur dioxide levels and as an alternative waste management method. In this study, the first stage was producing granular activated carbon from peanut shell at different parameters such as: activation temperature (500 o o o C, 600 C and 700 C), KOH concentration (25, 50 and75%wt.) and particle size (0.5, 1.5 and 2.5mm). Low ash content (1.28%) with high percent of methylene blue adsorption (79.4%) of activated carbon was obtained having 0.5mm particle size, 0.26%wt. KOH, and 600 o C of activation temperature was with 0.965 desirability chosen as optimal activation parameter. The activated carbon at optimal condition was characterized in term of ultimate and proximate analysis, FT-IR and methylene blue adsorption efficiency. Using activated carbon, the effect of various process parameters like temperature, activated carbon dosage and time on decolorization of cane syrup was investigated. Under the experimental conditions of 45 o C, 1.4g activated carbon dosage for 75min was found to be the optimal condition for maximum cane syrup decolorization efficiency (75.5%). Consequently, the experimental results indicated that the peanut shell has a potential to be used as an activated carbon for decolorization of cane syrup.
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    Optimal Removal of Methylene Blue in Aqueous Solution Using Selected Rice Husk Activated Carbon from Pore Development Agent.
    (Addis Ababa University, 2019-11) Alemie, Desalgne; Shegaw, Ahmed (PhD)
    In this study, the possible utilization of rice husk activated carbon as an adsorbent for the optimum removal of methylene blue dye from aqueous solutions has been investigated. Selective criterions for rice husk activated carbon (AC) were carried out as follows: Porous characteristics by, Brunauer-Emmett-Teller (BET) total surface area analyzer, surface structure using Scanning Electron Microscope (SEM) and surface functional group using Fourier Transform Infrared Spectroscopy (FT-IR) analysis. The batch adsorption studies of methylene blue (MB) carried out by selected porous ZnCl2 treated activated carbon. CCD at three-level and four factors were used to design the experiment to develop model equations for MB removal. The AC was initially prepared through chemical activation using zinc chloride (AC-ZC), phosphoric acid (AC-PA), and potassium hydroxide (ACPH) activating agents at optimal conditions of (carbonization temperature 500 C and holding time 60 min). The TSA were measured on BET 603 m o 2 2 /g, 545 m /g 2 and 498 m /g respectively. The optimal results in effect of process parameters of the analysis were for optimum adsorption of MB on selected porous AC-ZC 98.9 %, pH 8.69, adsorbent dose 1.9 g, and concentration of MB 11.63 g/ml and contact time 51 min. The results conclude the locally studied activated carbon of rice husk could be employed as low-cost alternatives to commercially imported activated carbon for the removal of basic dyes during wastewater treatment. This low cost and effective removal method may provide a promising solution for the removal of dye from wastewater.
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    Statical Process Optimization on Adsorption of Phenol from Water Using Activated Carbon Prepared from False Banana (Enseteventricosum) Leaf
    (Addis Ababa University, 2023-10) Mohammed Keder; Anteneh Wodaje (PhD)
    The reason for this current study was to examine the potential of an adsorbent produced from EL to recover phenol from wastewater. Using agricultural wastes as valuable resources to create ACs from biomass wastes is one of the greenest resolutions. The main objective of this study was to use a chemical activation technique to produce ACs from readily available waste EL. An essential property for the synthesis of AC is the EL's cellulose concentration (18.4%), lignin level (10.3%), MC of 8.35%, VM of 71.09%, AC of 3.28%, FCC of 17.28%, and yield of 49.30% at 400°C. With a nitrogen flow rate of 150ml/min, the process of carbonization was conducted for 30, 60, and 90minutes at 400, 500, and 600°C. The char product was treated with 37% phosphoric acid (H3PO4) at diverse impregnation ratios (0.5, 1 and 1.5). It was found that 500°C, a 60-minute contact period, and an impregnation ratio of 1 in AC5 were ideal for the production of AC. With respect to surface area (1023m2/g), iodine number (984mg/g), and total pore volume (0.45cm3/g), AC5 was the largest. Scanning electron microscopy (SEM) analysis showed that the samples' uneven surface structure. Several functional groups that aid in adsorption was found when Fourier Transform Infrared Spectroscopy (FTIR) was examined. Using phenol as a separate adsorbate and the ideal conditions (PH=6, adsorbent dosage=0.4g, initial concentration=10mg/l, and contact time=120min) at room temperature, the adsorption capacity of generated activated carbon (AC5) was investigated. It was demonstrated that as initial concentration increased, the capacity of adsorption increased. The maximal phenol elimination capability of the AC5 adsorbent is 95%. With the aid of the model, a relationship between the three experimental variables and the percentage of elimination was constructed. It looked into the phenol adsorption equilibrium isotherms utilizing the Freundlich, Temkin, and Langmuir isotherm models. For the concentration range of 10-150 mg/L, the monolayer adsorption capacity was 5.80mg/g, according to equilibrium data that followed the Langmuir model. There were kinetic analyses done. It was discovered that the data fit a pseudo-second order model. The best phenol elimination was obtained with an initial phenol PH of 6 and contact duration of 80 minutes. The study concluded that phenol could be effectively removed from aqueous solutions using activated carbon obtained from discarded Enset leaves.