Feed Flow Research Articles

The design and control of heat-integrated EDWC processes for the separation of THF/IPA/water

Extractive dividing wall columns (EDWC) and heat integration are effective process intensification strategies for separating azeotropes. In this study, the steady-state and dynamic control for the separation of tetrahydrofuran/isopropanol/water using a combination of EDWC and heat integration with intermediate reboilers are systematically investigated. The feasibility of the extractive distillation process is evaluated by analyzing the thermodynamic characteristics of the mixture through phase diagrams, and the three-column extractive distillation (TCED) process is established as the basic process. To enhance the energy and economic efficiencies, as well as environmental sustainability, three improved processes are proposed. Compared with TCED, the optimal process (E-EDWC-HI2) reduces the total annual costs, energy consumption, and CO2 emissions by 22.35 %, 41.77 %, and 26.28 %, respectively. In addition, a dynamic control structure is proposed for the E-EDWC-HI2, which exhibits robustness against disturbances in the feed flow rate and composition. This study provides guidance for the design and dynamic control of complex distillation processes.

Machine learning‐aided process design using limited experimental data: A microwave‐assisted ammonia synthesis case study

AbstractAn open research question lies in how machine learning (ML) can accelerate the design optimization of chemical processes which are at very early experimental development stage with limited data availability. As an example, this article investigates the design of an intensified microwave‐assisted ammonia production reactor with 46 experimental data. We present an integrated approach of neural networks and synthetic minority oversampling technique to quantify the nonlinear input‐output relationships of this process. For ammonia concentration predictions at discrete operating conditions, the approach demonstrates 96.1% average accuracy over other ML methods (e.g., support vector regression 84.2%). The approach has also been applied for continuous optimization, identifying the optimal synthesis conditions at 597.37 K, 0.55MPa with feed flow rate of 1.67 ×10−3 m3/s kg and hydrogen to nitrogen ratio of 1 which is consistent with experimental observations. The data‐driven model enables to integrate this reactor with existing ammonia production infrastructure and benchmark with conventional techniques.

Formulation of synbiotic buttermilk powder with higher viability of probiotic cells

The present study focused on the use of trehalose (TRE), whey protein concentrate (WPC), pullulan (PUL), and calcium lactate gluconate (CAL) as a protectant in the formulation of synbiotic buttermilk powder by application of spray drying. The spray drying of the solution mixture was carried out at an inlet temperature of 150 °C, a feed flow rate of 15mL/min, and compressed air at 3 kg/cm2 while keeping the outlet temperature constant at 70 ± 5 °C. TRE4 + CAL0.5 showed good results with the viability of Bifidobacterium bifidum as 6.04 ± 0.13 after 16 weeks followed by TRE2 + CAL0.5, TRE4, CAL0.5, WPC6, PUL4, and Control. The addition of protectants and Fructooligosaccharide (FOS) as a prebiotic did not affect the powder properties. The moisture content, water activity, bulk density, hygroscopicity, solubility, particle size, and scanning electron microscopy (SEM) of SBMP were better than the control sample for 17 weeks. SEM results showed spherical shapes without any cracks for SBMP containing TRE4 + CAL0.5. The present work demonstrated that the formulation containing TRE4 + CAL0.5 showed excellent results in terms of the viability of probiotic cells and also physicochemical properties of powder during storage for 16 weeks at 4 ± 1 °C.

Reaction ignition during the oxidative coupling of methane over Mn–Na2WO4/SiO2

The present study investigates the oxidative coupling of methane (OCM) as a viable solution for CH4 upgrading with the benchmark Mn–Na2WO4/SiO2 catalyst. The effects of space velocity on catalytic performance and ignition responses were evaluated. Experimental catalytic tests revealed a complex relationship between space velocity and C2+ product yields and a self-igniting behavior when the reaction temperature reached about 700 °C. The results indicated that the temperature difference (∆T) between the catalyst bed and the flowing gas increased with the feed flow rate and decreased with dilution of the catalyst bed (increasing with catalyst loading), which can allow the reaction ignition at lower temperatures. The present study sheds light on the interplay between reaction conditions and the ignition behavior, providing valuable insights for optimization of OCM processes and catalyst development.

Engineering Optimization of Producing High-Purity Dichlorosilane in a Fixed-Bed Reactor by Trichlorosilane Decomposition.

High-purity dichlorosilane (DCS) is an important raw material for thin film deposition in the semiconductor industry, such as epitaxial silicon, which is mainly produced by trichlorosilane (TCS) catalytic decomposition in a fixed-bed reactor. The productivity of DCS is strongly dependent on the controlling of the TCS decomposition reaction process, associated with the cost in practical application. In this study, we have performed computational fluid dynamics (CFD) simulation on the TCS decomposition reaction kinetics in a cylindrical fixed-bed reactor, in which the effects of catalyst bed height, feed temperature, and feed flow rate are stressed to predict the conversion rate of TCS and the generation rate of DCS. This indicates that the increase of bed height helps the reaction to proceed adequately, but too large a bed height does not improve the DCS generation rate. Meanwhile, the feed temperature and reactor temperature have important effects on the DCS generation rate. However, it is found that changing the feed flow rate and L/D ratio cannot effectively improve the DCS generation rate while the bed volume remains constant. Furthermore, we have designed a fixed-bed reactor to verify the simulation results, which are in good agreement with each other. These results are of significance for the practical industrial production of high-purity DCS in a fixed-bed reactor.

The Efficiency of Polyester-Polysulfone Membranes, Coated with Crosslinked PVA Layers, in the Water Desalination by Pervaporation.

Composite polymer membranes were obtained using the so-called dry phase inversion and were used for desalination of diluted saline water solutions by pervaporation (PV) method. The tests used a two-layer backing, porous, ultrafiltration commercial membrane (PS20), which consisted of a supporting polyester layer and an active polysulfone layer. The active layer of PV membranes was obtained in an aqueous environment, in the presence of a surfactant, by cross-linking a 5 wt.% aqueous solution of polyvinyl alcohol (PVA)-using various amounts of cross-linking substances: 50 wt.% aqueous solutions of glutaraldehyde (GA) or citric acid (CA) or a 40 wt.% aqueous solution of glyoxal. An ethylene glycol oligomer (PEG 200) was also used to prepare active layers on PV membranes. Witch its help a chemically cross-linked hydrogel with PVA and cross-linking reagents (CA or GA) was formed and used as an active layer. The manufactured PV membranes (PVA/PSf/PES) were used in the desalination of water with a salinity of 35‱, which corresponds to the average salinity of oceans. The pervaporation method was used to examine the efficiency (productivity and selectivity) of the desalination process. The PV was carried at a temperature of 60 °C and a feed flow rate of 60 dm3/h while the membrane area was 0.005 m2. The following characteristic parameters of the membranes were determined: thickness, hydrophilicity (based on contact angle measurements), density, degree of swelling and cross-linking density and compared with the analogous properties of the initial PS20 backing membrane. The physical microstructure of the cross-section of the membranes was analyzed using scanning electron microscopy (SEM) method.

Influence of microbubble two-phase feed flow on reverse osmosis desalination using different salt concentrations

This study aims to implement microbubble two-phase flow in the feed stream to improve mass transfer and achieve improved reverse osmosis (RO) process performance. The swirl-flow microbubble generator (MBG), which can effectively generate microbubbles, is integrated into the conventional RO system and has experimentally proven its performance under various operating conditions. To investigate the influence of microbubbles in the feed stream on the RO process depending on the feed concentration, real seawater and two types of artificial brackish water were used as the feed solution. The formation of microbubble two-phase flows in the feed stream had a positive impact on the transmembrane flux and distillate water quality of the RO process; this demonstrates that improved mass transfer due to microbubbles introduced into the feed can effectively attenuate the concentration polarization effect in the RO process. MBG-RO performance using seawater as the feed solution was found to be more pronounced at lower feed pressures and higher airflow rates, with an improvement in permeation flux of up to 16 %. Meanwhile, the MBG contribution to RO performance was lower when using artificial brackish water with relatively low concentration than that when using seawater.

Clarification of apple juice using cold plasma treated mixed cellulose esters membrane: flux modeling, membrane fouling, and juice physicochemical properties evaluation

This study aimed to clarify apple juice using unmodified and low-pressure cold plasma (gas: air, power: 10 W, and exposure time: 180 s) surface-modified mixed cellulose esters (MCE) microfiltration membranes. The effect of feed pressure (20, 40, and 60 kPa), feed flow rate (10, 15, and 20 mL/s), and feed temperature (27 and 40°C) on the permeate flux was evaluated using response surface methodology (RSM). The binary interaction of feed pressure and temperature and the second-order (non-linear) interaction of feed pressure and flow rate had a significant effect on the permeate flux (P<0.05). Generally, the process at 60 kPa, 15 mL/s, and 40 °C resulted in the maximum permeate flux. The cold plasma surface modification of the MCE membrane increased the permeate flux by about 45% at the optimum process conditions. Evaluation of membrane fouling showed that the cake formation was the predominant membrane fouling mechanism during both membrane processing. The physicochemical properties evaluation revealed that the surface-modified membrane produced clarified apple juice with antioxidant activity, reducing sugars, total sugars, phenolic, and vitamin C contents about 18.87%, 12.9%, 15.49%, 24.53%, and 45.15% more than clarified apple juice produced with unmodified MCE membrane, respectively.

Scale-bridging And Modelling Study of Graphene Shell Composite Adsorption for Dye Removal in Water Treatment

Continuous fixed-bed adsorption is a cost-effective water-treatment method for dye removal. This research examined parameters such as bed heights (5, 7, and 9cm), initial methylene blue (MB) concentrations (10, 15, and 20mg/L), and feed flow rates (8, 10, 12 and mL/min) on fixed-bed adsorption performance. Our findings showed that the performance was improved under longer exhaustion times not only with increasing column bed heights, but also with decreasing initial MB concentrations and feed flow rates. Of note, the Thomas and Yoon-Nelson models accurately described MB adsorption in a fixed-bed column, with R2 values from 0.7525 to 0.9833. Response surface methodology via central composite design optimized column bed heights and feed flow rates on the duration required to achieve 50% of column breakthrough. The coefficient of determination (R2) and analysis of variance demonstrated the significance of the Two Factor Interaction (2FI) model in fitting the actual values. The optimum conditions were determined to be as follows: a bed height of 5cm; a feed flow rate of 8mL/min; and a duration of 54.74min to achieve 50% of column breakthrough. Lastly, a confirmatory test further verified the precision of the proposed optimum conditions with an error of only 0.02%.

Citric acid functionalized chitosan hydrogel beads for enhanced Cr(VI) removal: Experimental assessment and COMSOL modelling of adsorption in a fixed-bed system

Chitosan hydrogel beads (CHB) and cross-linked CHB functionalized with tricarboxylic citric acid (CA-GLA-CHB) were synthesized and used for the removal of Cr(VI) from aqueous solutions in batch and dynamic adsorption systems. Applicability of COMSOL Multiphysics software as a tool for predictive modelling of column dynamics using a minimum set of experimental parameters was tested and compared with experimental results. Batch experiments demonstrated that CA-GLA-CHB showed almost 20% higher adsorption capacity and wider operational pH range compared to non-functionalized CHB. In a dynamic system, CA-GLA-CHB was used as column packing material and the column dynamics was investigated at different conditions. The breakthrough and exhaustion time of the column increased with an increase in bed height and a decrease in feed flow rate and initial Cr(VI) concentration. Computational modeling by COMSOL software with implemented Advection-Dispersion-Reaction (ADR) equation was used to simulate breakthrough curves for the applied dynamic system in order to validate the possibility of its application for process design in the scaled-up fixed-bed column systems for wastewater treatment. The simulated breakthrough curves of Cr(VI) adsorption matched well with the experimental, thus proving that COMSOL Multiphysics software can be used for scaling-up fixed-bed column systems packed with low-cost and effective CA-GLA-CHB bioadsorbent.

Enhanced continuous lithium extraction using self-designed porous nanosorbent fibers in a fixed-bed system: Optimization and mechanistic insights

This study introduced a novel lithium/aluminum layered double hydroxide (Li/Al-LDH) nanosorbent fiber (Li-PNF) engineered for continuous lithium extraction from brine using a fixed-bed system. These fibers featured a three-dimensional interconnected mesh structure and were distinctively encapsulated with needle-like Li/Al-LDH, exhibiting a layer-by-layer configuration. Compared to conventional Li/Al-LDH, Li-PNFs demonstrated abundant mesoporous structure and larger average pore size, facilitating the mass transfer and molecular diffusion of Li+ ions. Li-PNFs possessed a static lithium adsorption capacity of approximately 13.0 mg/g, with notable selectivity against Na+ and K+. Additionally, the Li+ binding energy across three distinct sites within the atomic structure of Li-PNFs proved advantageous, particularly at the Triangle-site-Al-overlapping-O3, which reached −5.72 eV. Fixed-bed adsorption experiments confirmed that lower feed flow rates, higher initial lithium concentrations, and increased bed heights significantly enhanced the Li+ capture efficiency, achieving up to 23.83 % in a single fixed-bed experiment. Based on the prediction of adsorption penetration curves using four empirical models, it was found that the Clark and Thomas models could accurately predict the behavior of Li+ penetration through the bed. Fixed-bed desorption results indicated that optimal lithium recovery was achieved at lower feed rates, reduced lithium concentrations in the desorption solution, and elevated temperatures. Finally, the excellent cyclic adsorption/desorption performance and low preparation cost of Li-PNF further highlighted its potential for real industrial applications, offering a significant advancement in the field of lithium extraction technology.

Cs‐Promoted Co Particles on Yttria‐Stabilized Zirconia as Coke‐Tolerance Methane Dry Reforming Catalyst under Elevated Pressure

Methane reforming with CO2 (dry reforming) co‐converts the two green‐house gases into synthesis gas and offers a promising way to integrate CO2 utilization into the current chemical infrastructure. One major obstacle for its industrial deployment is coke deposition on catalyst surface, in particular, under industrially relevant, pressurized operation conditions. Most catalytic investigations are conducted at atmospheric pressure, but the elevation in pressure poses a grand challenge for catalyst design. In this study, we demonstrate that Cs can promote carbon‐tolerance of Co catalyst supported on Yttria‐stabilized Zirconia under 20 bar, 850 oC with stochiometric feed flow for up to 100 h, which is often regarded as accelerated deactivation testing condition. Lowered amount and mostly CO2 gasifiable residue carbons are determined in Cs‐promoted spent Co‐catalyst, with respect to pristine Co catalyst. Kinetic studies reveal that Cs slows down coke deposition, while the essential reaction mechanism on pristine Co catalyst remains unaltered. Cs+ moieties absorb CO2 to afford Cs2CO3 that can release O* on adjacent Co surface to facilitate surface C* oxidation and simultaneously suppress carbon nucleation. The disclosure of the promoting effect of Cs on Co catalyst may have implications to other reforming catalyst and process design.

Evaluation of activated carbon fiber packed-bed for the treatment of gas-to-liquid wastewater: experimental, modeling and ASPEN Adsorption simulation

AbstractThis study investigates the continuous adsorption treatment of gas-to-liquid (GTL) wastewater from the Fischer-Tropsch process using activated carbon fiber (ACF) as the adsorbent. ACF, characterized by a high surface area of 1232 m²/g, was utilized to treat actual GTL wastewater, which contains long and short-chain alcohols, fatty acids, and other hydrocarbons. Experimental analysis, packed-bed modeling and simulation using ASPEN Adsorption were employed to understand the dynamics of the adsorption process. The experimental setup involved a bench-scale column packed with specified masses of ACF, with GTL wastewater pumped upward through the column at varying flow rates. Breakthrough curves were constructed to assess column performance, with parameters, such as feed flow rate (5 and 10 mL/min) and packing mass (5 and 10 g) systematically varied. The results demonstrate a significant influence of these parameters on column performance, with higher flow rates initially accelerating adsorption kinetics. Conversely, increasing packing mass extends the duration of column saturation, improving efficiency. Empirical models, including the Yoon-Nelson and El-Naas et al. models were applied to fit the experimental data, with the latter showing superior performance in representing the adsorption mechanism within the column. Quantitative analysis of model fitting using Akaike Information Criteria (AIC) identified the Yoon-Nelson and El-Naas et al. model as the most suitable for describing the GTL wastewater/ACF system, with an AIC weight parameter of 0.33 and R2 averaging 86.5%. Furthermore, simulation results from ASPEN Adsorption exhibited strong agreement with experimental data, validating its efficacy for simulating liquid adsorption processes. The study provides valuable insights into the design and optimization of large-scale wastewater treatment systems, offering practical solutions to address global water challenges.

Enhanced Glycerolysis of Fatty Acid Methyl Ester by Static Mixer Reactor.

This study investigates the synthesis of monoglycerides (MGs) and diglycerides (DGs) from glycerol (G) and fatty acid methyl ester (FAME) using a static mixer reactor (SMR), which combines a static mixer (SM) with a reactor tank. The SMR integrates Kenics static mixers (KSM) and low-pressure drop static mixers (LPDSM) with varying length-to-diameter ratios (L/D = 1.0 and 1.5). Keys glycerolysis parameters, including the G:FAME molar ratio of 2:1-3:1, 2-3 wt % potassium hydroxide (KOH), and reaction time of 30-90 min at 150 °C were systematically explored. The SMR design allows precise control over the reaction time without altering the feed flow rate or tube length and avoiding agitator leakage. The optimal operating conditions, determined through a face-centered central composite design, resulted in 71.35% MGs and 14.20% DGs at a 3:1 molar ratio of G to FAME, 3 wt % KOH, 60 min, and 150 °C using an LPDSM with an L/D of 1.5. In comparison, an LPDSM with an L/D of 1 achieved 79.28% MGs and 10.17% DGs under the same conditions. When applied to purified crude glycerol, these conditions yielded 61.09% MGs and 23.44% DGs. The study found that a lower L/D ratio improved the mixing efficiency but increased the pressure drop. The SMR demonstrated superior performance in glycerolysis compared with conventional stirred tank reactors and ultrasonic probe reactors, indicating its potential for enhanced industrial application.

Reverse water-gas shift in a novel spark-coupled dielectric barrier discharge plasma: Effects of electrode structure and gas parameters

The reverse water–gas shift (RWGS) reaction holds promise for producing raw materials used in the synthesis of high-value chemicals. However, the reaction is often hindered by low CO2 conversion rates at atmospheric pressure and low temperatures. To overcome this limitation, this study developed a novel reactor based on strengthened spark-coupled dielectric barrier discharge (SSCDBD) without a catalyst, leveraging local high temperatures to enhance performance. The effects of reactor structure and gas parameters on conversion rate and energy efficiency were systematically investigated. The results indicated that the SSCDBD device notably improved CO2 conversion compared to conventional plasma techniques, such as dielectric barrier discharge (DBD), spark discharge, and spark-coupled dielectric barrier discharge (SCDBD), with respective increases of 1000 %, 12.65 %, and 2.79 %. Notably, varying the length of the auxiliary electrode affects the capacitance of the equivalent capacitor and, consequently, the discharge intensity. Furthermore, Increasing the electrode length from 4 cm to 20 cm improved the CO2 conversion rate from 43.7 % to 59.8 %. Moreover, CO2 conversion was positively correlated with the discharge distance, which also affected the volume of the electric arc. However, distances exceeding 1.2 cm interfered with arc formation. At a CO2:H2 molar ratio of 1:1, with an auxiliary electrode length of 12 cm and a discharge distance of 0.8 cm, the maximum CO2 conversion rate of 66 % was achieved at a total feed flow rate of 100 mL min−1, while maintaining a CO selectivity higher than 99 %. Additionally, with a total feed flow rate of 400 mL min−1, CO2 conversion reached 29 % and energy efficiency peaked at 6.34 %.

Plasma-assisted NH3 cracking in warm plasma reactors for green H2 production

NH3 is emerging as a carrier of green H2, but it requires a green and economical NH3 cracking process based on renewable energy. Plasma technology is promising for this purpose, as it can crack NH3 without the need for a catalyst and is highly compatible with renewable electricity, reducing the environmental footprint of the cracking process. This work investigates the NH3 cracking performance of four different warm plasma reactors with different configurations and operating in a wide range of conditions. We show that the NH3 conversion in warm plasma reactors is primarily determined by the specific energy input, with the main difference observed in the energy cost (EC) of cracking. The lowest EC obtained is 146 kJ/mol but at a conversion of only 8 %. A more reasonable conversion of around 50 % yields an EC of around 200 kJ/mol in two of the reactors investigated. Plasma reactors operating at higher feed flow rates are more efficient and yield a higher H2 production rate. Our data indicate that NH3 cracking in these warm plasma reactors occurs mainly via thermal chemistry, with non-thermal plasma chemistry playing a less prominent role. NH3 decomposes not only inside the plasma core but also in a hot volume around it, which reduces the EC. Our study shows that warm plasmas are significantly more efficient for NH3 cracking than cold plasmas, even when the latter are combined with catalysts.

Combining Ultra-Turrax and ultrasonic homogenization to achieve higher vitamin E encapsulation efficiency in spray drying

Vitamin E, a soluble antioxidant widely used in the food and pharmaceutical industries, is rich in tocopherols and phytosterols. Since vitamin E molecules are highly sensitive to oxidation, encapsulation is a viable and effective technique for preservation of the properties of Vitamin E and improving its stability during storage, maintaining the nutritional value. In this work, the aim was to encapsulate concentrated vitamin E using a combination of Ultra-Turrax and ultrasonication to achieve higher encapsulation efficiency in spray drying. In the first stage, the vitamin E oil was encapsulated employing only Ultra-Turrax homogenization, with subsequent optimization of spray drying. The coating materials used were maltodextrin and whey protein isolate. Optimization of the spray drying step evaluated the effects of the drying air temperature (T) and the feed flow rate (Q), to obtain better yields and a high-quality product. In the second stage, the use of ultrasonication in an additional homogenization step was evaluated, aiming to further improve the encapsulation process. The results showed that the best drying conditions (first stage) were T = 180 °C and Q = 0.6 L/h, which provided the highest yield (67.73%) and high encapsulation efficiency (73.73%). The microspheres produced had similar properties, with mean diameters ranging from 0.64 to 12.99 μm. In the second stage of the investigation, the application of ultrasonication immediately after the Ultra-Turrax homogenization enabled the encapsulation efficiency to be increased to 94.05%, with a yield of 57.54%, using an ultrasonication time of only 7 min. This showed that addition of the ultrasonic homogenization step to the process greatly improved the encapsulation efficiency and could be used to produce vitamin E-enriched powder microcapsules by spray drying, with application in the food industry.

Regeneration of CO2 from CO2-rich absorbents using hollow fiber membrane contactors in liquid–liquid extraction mode

This study explores the use of hollow fiber membrane contactors (HFMCs) to efficiently regenerate CO2 from CO2-rich absorbents and convert it into calcium carbonate (CaCO3) via a novel liquid–liquid extraction process. CO2 is absorbed into a potassium carbonate (K2CO3) solution and then desorbed directly into a calcium chloride (CaCl2) solution through a porous polypropylene (PP) hollow fiber membrane. This single-step process significantly reduces the energy costs associated with traditional CO2 chemical capture methods, such as reboilers and gas compression. Key operational parameters, including stripping liquid chemistry (Ca2+ concentration and pH), feed liquid temperature, and HFMC stages, were optimized. CO2 regeneration peaked at pH 11.0 with a Ca2+ concentration of 108.00 mmol/L, achieving a 37 % efficiency at 80 ℃ in a single-stage HFMC. A three-stage HFMC in parallel mode increased CO2 regeneration efficiency to 49 %, though with a lower Ca2+ carbonation efficiency of 2.92 %. The open-loop configuration, which facilitates continuous CO2 absorption from flue gas, demonstrated practical application potential, regenerating approximately 30 % CO2 at a feed flow rate of 0.3 cm/s.

Comparative Studies of Diclofenac Sodium (NSAID) Adsorption on Wheat (Triticum aestivum) Bran and Groundnut (Arachis hypogaea) Shell Powder using Vertical and Sequential Bed Column

Wheat bran and groundnut shell powder have been used to study the mechanism of diclofenac sodium adsorption from aqueous solution using batch as well as column modes and maximum uptake is 84.3% for wheat bran and 82.4% for groundnut shell powder at pH 6, drug concentration 1 mg/L at 298 K for 30min. Isotherm and error analysis reveals that Freundlich and Langmuir isotherms fitted well. Kinetic studies show that the adsorption process follows second-order kinetics and thermodynamic study shows endothermic adsorption process. Column adsorption study is important for industrial scale adsorption and column studies have been carried out using vertical bed and sequential bed adsorption columns at pH 6 which is the optimum pH for maximum adsorption for batch experiments. Vertical and sequential bed columns setup is simple and economical which provides flow under gravity. The effect of varying inlet feed concentration and flow rate on the breakthrough and exhaustion time of columns has been studied to determine the bed capacities of both columns. Thomas model and Yoon-Nelson models fitted well with experimental data for continuous flow column studies.

Performance of combined organic precipitation, electrocoagulation, and electrooxidation in treating anaerobically treated palm oil mill effluents

Palm oil mill effluent (POME), wastewater generated from palm oil production, is known for its extremely high chemical oxygen demand and brownish color. Anaerobic digestion is the primary treatment method for POME in the palm oil industry; however, anaerobically treated POME has high concentrations of residual contaminants and color intensity. This study proposes an approach to treat anaerobically-treated POME in recycled water for industrial applications by integrating preliminary organic precipitation, electrocoagulation, and electrooxidation (EO). The EO process was optimized in terms of the current density, electrolysis time, electrode arrangement, and feed flow rate. At a current density of 60 mA/cm2 and an electrolysis time of 9 min, the EO process with a graphite anode and stainless-steel cathode in the monopolar electrode configuration reduced the phenolic concentration and color in the preliminary-treated POME from 8.95 mg/L and 317.19 ADMI to 0.25 mg/L and 26.10 ADMI, respectively. Additionally, the EO process exhibited a 92.26% efficiency in lowering the ammonium-nitrogen content.