Tubular Reactor Research Articles

Integration of a perfusion reactor and continuous precipitation in an entirely membrane-based process for antibody capture.

Continuous precipitation coupled with continuous tangential flow filtration is a cost-effective alternative for the capture of recombinant antibodies from crude cell culture supernatant. The removal of surge tanks between unit operations, by the adoption of tubular reactors, maintains a continuous harvest and mass flow of product with the advantage of a narrow residence time distribution (RTD). We developed a continuous process implementing two orthogonal precipitation methods, CaCl2 precipitation for removal of host-cell DNA and polyethylene glycol (PEG) for capturing the recombinant antibody, with no influence on the glycosylation profile. Our lab-scale prototype consisting of two tubular reactors and two stages of tangential flow microfiltration was continuously operated for up to 8 days in a truly continuous fashion and without any product flow interruption, both as a stand-alone capture and as an integrated perfusion-capture. Furthermore, we explored the use of a negatively charged membrane adsorber for flow-through anion exchange as first polishing step. We obtained a product recovery of approximately 80% and constant product quality, with more than two logarithmic reduction values (LRVs) for both host-cell proteins and host-cell DNA by the combination of the precipitation-based capture and the first polishing step.

Influence of the diameter of a tubular reactor and the direction of front propagation on the process of frontal copolymerization of acrylamide with sodium acrylate in aqueous solutions

The objects of study were the process of frontal copolymerization of acrylamide with sodium acrylate in aqueous solutions in tubular reactors of various diameters and with different directions of front propagation, as well as the resulting copolymers and hydrogels. The effect of the diameter of a tubular reactor and the direction of front propagation on the process of frontal copolymerization of acrylamide and sodium acrylate in aqueous solutions has been studied. It was shown that the front velocity is almost independent of the diameter of the tubular reactor, and the front temperature decreases with increasing diameter. The values of water absorption and gel-fraction of the obtained hydrogels were determined.

Thermal performance of a metal hydride reactor for hydrogen storage with cooling/heating by natural convection

Metal hydride (MH) systems can be used for storage in stationary facilities of hydrogen with a high volume density at temperatures and pressures close to ambient ones. Recently, the possibility of using passive heating/cooling systems or regenerative heat exchangers has been studied to improve the energy efficiency of MH systems for hydrogen storage without the need for forced circulation of a heating/cooling fluid. Natural convection of air may be used to passively remove/add heat as required for proper operation of a MH reactor. Under these conditions, the MH reactor can operate at a constant ambient air temperature and be driven by a difference in pressure between the source and the consumer of hydrogen. Since operation of MH systems with natural convective heating/cooling has not been systematically investigated as yet, a tubular MH reactor based on this principle is examined in this paper. Two-thirds of the internal volume of ø25.4 × 1 mm tube is occupied by a composition of LaNi5 and aluminium foam (one linear metre contains 1.1 kg of LaNi5 with a hydrogen capacity of 153 NL H2). Annular fins are used to increase heat transfer to air. Detailed and simplified mathematical models of the systems of this class are proposed and validated. It is shown that acceptable hydrogen charging/discharging rates in such systems are achieved with proper selection of fining characteristics. Charging from a hydrogen source at a pressure of 10 atm and an ambient air temperature of 10 to 30 °C takes 15 min. A reactor with a length of 1 m can desorb almost all stored hydrogen at a minimum outlet pressure of 0.45 bar to feed 30–300 W fuel cells.

Inverse Miniemulsion Enables the Continuous-Flow Synthesis of Controlled Ultra-High Molecular Weight Polymers.

We report the controlled synthesis of ultra-high molecular weight (UHMW) polymers (Mn ≥ 106 g/mol) via continuous flow in a tubular reactor. At high monomer conversion, UHMW polymers in homogeneous batch polymerization exhibit high viscosities that pose challenges for employing continuous flow reactors. However, under heterogeneous inverse miniemulsion (IME) conditions, UHMW polymers can be produced within the dispersed phase, while the viscosity of the heterogeneous mixture remains approximately the same as the viscosity of the continuous phase. Conducting such IME polymerizations in flow results in a faster rate of polymerization compared to batch IME polymerizations while still providing excellent control over molecular weight up to 106 g/mol. Crucial emulsion parameters, such as particle size and stability under continuous flow conditions, were examined using dynamic light scattering. A range of poly(N,N-dimethylacrylamide) and poly(4-acryloylmorpholine) polymers with molecular weights of 104-106 g/mol (Đ ≤ 1.31) were produced by this method using water-soluble trithiocarbonates as photoiniferters.

Non-Catalytic and Catalytic Conversion of Fruit Waste to Synthetic Liquid Fuel via Pyrolysis

Plum stone stands out as an alternative biomass source in terms of obtaining fuel and chemicals with or without catalysts under different conditions. Under variable heating rates (10, 50, and 100 °C min−1) and pyrolysis temperatures (400, 450, 500, 550, and 600 °C), plum stone was pyrolyzed at a constant rate in a constant sweep gas flow (100 cm3 min−1) in a tubular fixed-bed reactor. According to the results, an oil yield reaching a maximum of 45% was obtained at a heating rate of 100 °C min−1 and pyrolysis temperature of 550 °C in the non-catalytic procedure. The catalytic pyrolysis was carried out with two selected commercial catalysts, namely ZSM-5 and PURMOL-CTX and clinoptilolite (natural zeolite, NZ) under optimum conditions with a catalyst ratio of 10% of the raw material. With the addition of catalyst, the quantity and quality of bio-oil increased, including calorific capacity, the removal of oxygenated groups, and hydrocarbon distribution. In the presence of catalysts, an increase was observed in terms of desirable products such as phenol, alkene, and alkane, and a decrease in terms of undesirable products such as acids. Considering and evaluating all the results, the use of zeolite materials as catalysts in pyrolysis is a recommended option for obtaining enhanced chemicals and fuels.

Effect of Micro-Nanobubbles on Arsenic Removal by Trichoderma atroviride for Bioscorodite Generation.

The global environmental issue of arsenic (As) contamination in drinking water is a significant problem that requires attention. Therefore, the aim of this research was to address the application of a sustainable methodology for arsenic removal through mycoremediation aerated with micro-nanobubbles (MNBs), leading to bioscorodite (FeAsO4·2H2O) generation. To achieve this, the fungus Trichoderma atroviride was cultivated in a medium amended with 1 g/L of As(III) and 8.5 g/L of Fe(II) salts at 28 °C for 5 days in a tubular reactor equipped with an air MNBs diffuser (TR-MNBs). A control was performed using shaking flasks (SF) at 120 rpm. A reaction was conducted at 92 °C for 32 h for bioscorodite synthesis, followed by further characterization of crystals through Fourier-Transform Infrared Spectroscopy (FTIR), Scanning Electron Microscopy (SEM), and X-ray diffraction (XRD) analyses. At the end of the fungal growth in the TR-MNBs, the pH decreased to 2.7-3.0, and the oxidation-reduction potential (ORP) reached a value of 306 mV at 5 days. Arsenic decreased by 70%, attributed to possible adsorption through rapid complexation of oxidized As(V) with the exchangeable ferrihydrite ((Fe(III))4-5(OH,O)12), sites, and the fungal biomass. This mineral might be produced under oxidizing and acidic conditions, with a high iron concentration (As:Fe molar ratio = 0.14). The crystals produced in the reaction using the TR-MNBs culture broth and characterized by SEM, XRD, and FTIR revealed the morphology, pattern, and As-O-Fe vibration bands typical of bioscorodite and römerite (Fe(II)(Fe(III))2(SO4)4·14H2O). Arsenic reduction in SF was 30%, with slight characteristics of bioscorodite. Consequently, further research should include integrating the TR-MNBs system into a pilot plant for arsenic removal from contaminated water.

Rapid Thermal Processing of Kesterite Thin Films

Multinary chalcogenides with Kesterite structure Cu2ZnSn(S,Se)4 (CZTSSe) are a prospective material base for the enhancement of the photovoltaics industry with abundant and environmentally friendly constituents and appropriate electro-physical properties for building highly efficient devices at a low cost with a short energy pay-back time. The actual record efficiency of 13.6%, which was reached recently, is far below the current isostructural chalcopyrite’s solar cells efficiency of near 24%. The main problems for future improvements are the defects in and stability of the Kesterite absorber itself and recombination losses at interfaces at the buffer and back contacts. Here, we present an investigation into the rapid thermal annealing (RTA) of as-electrodeposited thin films of Cu2ZnSnS4 (CZTS). The treatment was carried out in a cold wall tubular reactor in dynamic conditions with variations in the temperature, speed and time of the specific elements of the process. The effect of annealing was investigated by X-ray diffractometry, Raman scattering and Scanning Electron Microscopy (SEM). The phase composition of the films depending on treatment conditions was analyzed, showing that, in a slow, prolonged, high-temperature process, the low-temperature binaries react completely and only Kesterite and ZnS are left. In addition, structural investigations by XRD have shown a gradual decrease in crystallite sizes when the temperature level and duration of the high-temperature segment increases, and respectively increase in the strain due to the formation of the phases in non-equilibrium conditions. However, when the speed of dynamic segments in the process decreases, both the crystallite size and strain of the Kesterite non-monotonically decrease. The grain sizes of Kesterite, presented by SEM investigations, have been shown to increase when the temperature and the duration increase, while the speed decreases, except at higher temperatures of near 750 °C. The set of experiments, following a scrupulous analysis of Raman data, were shown to have the potential to elucidate a way to ensure the fine manipulation of the substitutional Cu/Zn defects in the structure of CZTS thin films, considering the dependences of the ratios of Q = I287/I303 and Q′ = I338/(I366 + I374) on the process variables. Qualitatively, it can be concluded that increases in the speed, duration and temperature of RTA lead to increases in the order of the structure, whereas, at higher temperatures of near 750 °C, these factors decrease.

High-temperature corrosion behavior of S30432 in high-efficiency ultra-supercritical boiler burning low-alkali and high-sulfur coal

Abstract In this study, the resistance of S30432 to low-alkali coal ash corrosion in a high-efficiency USC boiler was investigated. Currently, S30432 is widely used in the high-temperature superheater and reheater of boilers burning low-alkali and high-sulfur coal. During the experiment, S30432 coated with low-alkali coal ash were fixed in a high-temperature tubular reactor, and hot gas at 650 °C and 700 °C containing SO2 passed over the specimens for 2000 h. Then the specimens were tested by X-ray diffraction, scanning electron microscopy, and energy-dispersive spectroscopy. It was found that S30432 specimens mainly underwent high-temperature oxidation. For the gas temperature of 700 °C and SO2 volume concentration of 0.35 %, the sulfidation reaction occurred and the weight change was only 1.08 mg cm−2. The results show that there is no obvious high-temperature corrosion after three years of operation of a 700 MW 620 °C boiler. The results are in contrast with the high-alkali coal ash corrosion resistance of S30432. It is concluded that S30432 can meet the requirements of a high-efficiency USC boiler burning low-alkali and high-sulfur coal.

Effect of Microwave Heating on the Residence Time Distribution in a Tubular Reactor

Effect of Microwave Heating on the Residence Time Distribution in a Tubular Reactor

Comprehensive study on catalytic coating tubular reactor with electromagnetic induction heating for hydrogen production through methanol steam reforming

This study presents an induction heating-based reactor for on-board methanol steam reforming for hydrogen production reactors and distributed hydrogen refueling stations, with the goal of developing a hydrogen production process with zero carbon emissions. The numerical results showed that the enhanced hydrogen production performance and temperature cold spots could be eliminated, and the methanol conversion was close to 100%. at 150 A and 20 kHz. Induction heating may significantly shorten the reactor's cold start-up time. Under 50 kHz, the temperature of the reactor wall can reach more than 500 K in 50 s, in other words, induction heating overcomes the problems of slowly heating/cooling rate for on-board methanol steam reforming for hydrogen generation reactors. Overall, this study supports the feasibility of producing green hydrogen with zero carbon emissions for advancing the development of an environmental hydrogen economy and the cold start-up of distributed hydrogen energy and vehicle-used hydrogen production equipment.

Continuous precipitation-filtration process for initial capture of a monoclonal antibody product using a four-stage countercurrent hollow fiber membrane washing step.

The significant increase in product titers, coupled with the growing focus on continuous bioprocessing, has renewed interest in using precipitation as a low-cost alternative to Protein A chromatography for the primary capture of monoclonal antibody (mAb) products. In this work, a commercially relevant mAb was purified from clarified cell culture fluid using a tubular flow precipitation reactor with dewatering and washing provided by tangential flow microfiltration. The particle morphology was evaluated using an inline high-resolution optical probe, providing quantitative data on the particle size distribution throughout the precipitation process. Data were obtained in both a lab-built 2-stage countercurrent washing system and a commercial countercurrent contacting skid that provided 4 stages of continuous washing. The processes were operated continuously for 2 h with overall mAb yield of 92 ± 3% and DNA removal of nearly 3 logs in the 4-stage system. The high DNA clearance was achieved by selective redissolution of the mAb using a low pH acetate buffer. Host cell protein clearance was 0.59 ± 0.08 logs, comparable to that based on model predictions. The process mass intensity was slightly better than typical Protein A processes and could be significantly improved by preconcentration of the antibody feed material.

Supercritical water oxidation for the destruction of spent media wastes generated from PFAS treatment

Granular activated carbon (GAC) and anion exchange resin (AIX) have been successfully demonstrated to remove per- and polyfluoroalkyl substances (PFAS) from contaminated water and wastewater. These treatment technologies, when applied for PFAS removal, generate spent media loaded with a high mass of PFAS requiring further treatment and disposal. This project is the first study on the use of supercritical water oxidation (SCWO) to destroy both the spent media and the PFAS adsorbed onto it. One sample of spent GAC and one sample of spent AIX were collected from full-scale groundwater remediation systems treating PFAS. A second spent AIX sample was collected from a mobile PFAS treatment unit. The total PFAS concentrations reported in the GAC, AIX and second AIX feedstock slurries were 0.21 mg/kg, 1.3 mg/kg and 0.9 mg/kg, respectively. Each feedstock was processed separately in a one (1) wet metric ton per day tubular reactor SCWO system. The study demonstrated that SCWO is a very effective PFAS destruction technology for spent GAC and AIX, derived from water remediation systems treating PFAS. The spent media were completely mineralized to water, carbon dioxide (CO2) and a negligible amount of residual minerals. Total target PFAS compound concentrations in the SCWO system effluents after treating spent GAC, AIX and second AIX feedstocks were 548, 77 and 796 ng/L, respectively. The results indicated that the percentage elimination of perfluorocarboxylic acids (PFCAs) was better than that of perfluosulfonic acids (PFSAs) and long-chain PFAS elimination was better than short-chain PFAS.

Thermo-catalytic pyrolysis of Azadirachta indica seeds over CaO and CuO: Pyrolysis kinetics, impact of catalysts on yield, fuel properties and its chemical compositions

Pyrolysis oil and distribution is still in the incipient stages, though it is a potential source of energy and valueable chemicals. The current work focused on the kinetics study and thermo-catalytic pyrolysis of Azadirachta indica seeds (AZI) over CaO and CuO. The kinetic behaviour of AZI is studied in a TGA under an inert atmosphere at dynamic heating rates (10, 20 and 30 °C min−1) using Starink method (ST) and Vyazovkin model (VM). Further, AZI were pyrolyzed in a semi-batch tubular reactor at 500 °C, 50 °C min−1 heating rate and 100 mL min−1 nitrogen flow rate at 20 wt% catalyst loading. The biomass and pyrolysis liquid were characterised via proximate analysis, elemental analysis, thermal stability, FTIR, viscosity, density, acidity, moisture content, GC-MS etc. Kinetic analysis of AZIs confirmed that biomass decomposition takes place in a multifaceted route, and the activation energy is associated with conversion and temperature. Thermal pyrolysis exhibited 39.53 wt% liquid yields; however, introducing 20 wt% catalyst has improved the yield to 46.53 wt% and 45.36 wt% for CaO and CuO, respectively. The findings of the thermal and catalytic pyrolytic oil demonstrated that the addition of catalysts significantly enhanced the properties of pyrolytic oil by lowering viscosity and oxygen content while raising heating value and acidity. Finally, GC-MS results displayed that the use of catalysts resulted in a considerable decline in the proportion of oxygenated compounds, acids, and phenols and an increase in the proportion of hydrocarbons, aldehydes and alcohols.

Investigation of pyrolytic characteristics of three oily sludges with focus on properties of oil product

Pyrolysis is an important thermochemical conversion technology to recover the oily sludge resources and reduce the harmfulness of waste. This work aims to investigate the pyrolysis behaviors of three different oil sludges by using a thermogravimetric analyzer and two fixed-bed reactors. An attempt was made to determine a wide range of properties of liquid products. Three oily sludges included a tank bottom sediment (OS-1), an oil-water separator scum (OS-2), and a wastewater sediment concentrate (OS-3). OS-1 had a high content of oil, whereas OS-2 and OS-3 were characteristic of high contents of water and oxygen. The pyrolysis of as-received oily sludge in a vertical tubular reactor at 700 °C attained the oil yield up to 69.2 % for OS-1, against the oil yields ranged in 34.4–35.5 % for OS-2 and OS-3. These yields of pyrolysis oil were higher than or close to those of extraction oil. Through characterizing the molecular composition of pyrolysis oil and extraction oil, it was revealed that the pyrolysis promoted the cracking of long-chain alkanes and O/N-containing functional groups accompanied by the conjugation, cyclization and aromatization reactions. The analysis of the pyrolysis oils obtained from the horizontal tubular reactor showed that the liquid products derived from all three oil sludges had very low ash contents and viscosities, and the water-free pyrolysis oils had higher HHVs than the parent dried oil sludges.

Pilot-scale cultivation of the red alga Porphyridium purpureum over a two-year period in a greenhouse

Microalgae can form renewable feedstock for many sectors. However, most microalgae commercially cultivated are difficult to grow in colder climates. To overcome this problem one could cultivate cold tolerant algae. One such alga is the red marine alga Porphyridium purpureum. It is currently often cultivated in bag systems in limited volumes. In this study we cultivated P. purpureum at pilot-scale in horizontal tubular reactors in a greenhouse. P. purpureum was grown in batch mode in a total volume of either 350, 500, 1000 or 1500 L. A total of 28 batches, spread over two years, were cultivated reaching a maximum dry weight of 1.94 g L−1. The growth was continuously monitored to calculate the productivities and growth rates. The P and N concentrations were measured frequently during four batches to calculate the P and N usage per gram biomass. To calculate CO2 fixation efficiencies the total CO2 consumption was monitored during 6 of the 28 batches. A maximum productivity and growth rate of respectively 0.195 g L−1 day−1 and 0.233 day−1 were achieved while the P and N usage varied from 3.2–6.19 and 14.5–36.6 mg g−1 biomass for P and N, respectively. Growth was supported between 10 °C and 30 °C, while temperatures above 34—35 °C proved to be detrimental. The CO2 efficiencies differed among the 6 tested periods with the highest utilization efficiency being 13.5% and the lowest a mere 1.5%. Further large-scale, continuous, tests would be needed to fully optimize the cultivation of P. purpureum in larger volumes.

Assessment of the start-up of tubular reactors on a laboratory scale for the anaerobic digestion of slaughterhouse wastewater

Assessment of the start-up of tubular reactors on a laboratory scale for the anaerobic digestion of slaughterhouse wastewater

Upgrading Pyrolytic Oil via Catalytic Co-Pyrolysis of Beechwood and Polystyrene.

This study aims to investigate the catalytic co-pyrolysis of beech wood with polystyrene as a synergic and catalytic effect on liquid oil production. For this purpose, a tubular semi-continuous reactor under an inert nitrogen atmosphere was used. Several zeolite catalysts were modified via incipient wetness impregnation using iron and/or nickel. The liquid oil recovered was analyzed using GC-MS for the identification of the liquid products, and GC-FID was used for their quantification. The effects of catalyst type, beechwood-to-polystyrene ratio, and operating temperature were investigated. The results showed that the Fe/Ni-ZSM-5 catalyst had the best deoxygenation capability. The derived oil was mainly constituted of aromatics of about 92 wt.% for the 1:1 mixture of beechwood and polystyrene, with a remarkably high heating value of around 39 MJ/kg compared to 18 MJ/kg for beechwood-based bio-oil. The liquid oil experienced a great reduction in oxygen content of about 92% for the polystyrene-beechwood 50-50 mixture in comparison to beechwood alone. The catalytic and synergetic effects were more realized for high beechwood percentages as a 75-25 beechwood-polystyrene mix. Regarding the temperature variation between 450 and 600 °C, the catalyst seemed to deactivate faster at higher temperatures, thus constituting a quality reduction in the pyrolytic oil in high-temperature ranges.

Chromatography assisted in-vitro refolding and purification of recombinant peptibody: Recombinant Romiplostim a case study

In-vitro protein refolding is one of the key rate-limiting unit operations in manufacturing of fusion proteins such as peptibodies expressed using E. coli. Dilution-assisted refolding is the most commonly used industrial practice to achieve the soluble, native functional form of the recombinant protein from the inclusion bodies. This study is focused on developing a chromatography-assisted in-vitro refolding platform to produce the biologically active, native form of recombinant peptibody. Recombinant Romiplostim was selected as a model protein for the study. A plug flow tubular reactor was connected in series with capture step affinity chromatography to achieve simultaneous in-vitro refolding and capture step purification of recombinant Romiplostim. Effect of various critical process parameters like fold dilution, temperature, residence time, and Cysteine: DTT ratio was studied using a central composite based design of experiment strategy to achieve a maximum refolding yield of selected peptibody. Under optimum refolding conditions, the maximum refolding yield of 57.0 ± 1.5 % and a purity of over 79.73 ± 3.4 % were achieved at 25-fold dilution, 15 °C temperature, 6 h residence time with 6 mM and 10 mM of cysteine and DTT, respectively. The formation of native peptibody structure was examined using various orthogonal analytical tools to study the protein's primary, secondary, and tertiary structure. The amino acid sequence for the disulfide-linked peptide was mapped using collision-induced dissociation (CID) to confirm the formation of interchain disulfide bonds between Cys7-Cys7 and Cys10-Cys10 similarly for intra-chain disulfide bonds between Cys42-Cys102, and Cys148-Cys206. The developed protocol here is a valuable tool to identify high-yield scalable refolding conditions for multi-domain proteins involving inter-domain disulfide bonds.

Application of participatory design and open source to a sustainable proposal for sorption reactor design

An implementation proposal that seeks to globalize the scope of the sustainable technologies developed in the University laboratories is presented. This approach uses the generation of triple-impact projects placing people at the center of technological development to bring technical and scientific knowledge into a service design oriented to global sustainable solutions. This research is an approach to what a hub for scientific research, technological implementation, and human needs would look like by designing common environments in which to interact and expand knowledge in an iterated way through the experience of all the actors involved in technological implementation. As a control case, a new technology developed at the Universidad de Buenos Aires, consisting of using sustainable materials as tubular reactor fillers for water treatment was chosen. Based on data obtained within the framework of a University extension project, in which the water quality diagnosis for human consumption was carried out and cross-examined with the mathematical analysis of sorption, design parameters of the reactor, participatory design, and open source concepts application, different virtual environments were generated with distinct objectives: i) open design environment: publishing and mapping of installed sorption reactors, reactor model plans, and useful information related to drinking water quality (aimed at contributors of the open source design environment); ii) platform for academic actors linking: connecting data between prototyping lab for participatory design of sorption reactors (aimed at university research users); iii) information disclosure page: space where the implemented technology impact is displayed and shows options to contact researchers and request a reactor design diagnosis for another community (aimed at beneficiary users). A technological service designed to link the University with the community was proposed, by resolving one of the main gaps related to the possibility for communities to access public financing for self-managed improvement projects, increasing the appropriation of the adopted technology and democratizing public investment, making it sustainable over time.

Compact tubular carbon-based membrane bioreactors for the anaerobic decolorization of azo dyes

This research investigates a highly efficient compact tubular ceramic-supported carbon-based membrane reactor integrated with anaerobic biodegradation to decolorize the azo dyes. Two carbon-based membranes, produced using Matrimid 5218 polyimide and graphene oxide solutions, are evaluated for the comparative color removal of three structurally different azo dyes, Acid Orange 7 (AO7), Reactive Black 5 (RB5), and Direct Blue 71 (DB71). Based on FESEM microscopic images, the average pore size of the tubular ceramic-supported carbonized membrane (TCSCM) was approximately 25 nm, while for the tubular ceramic-supported graphene oxide membrane (TCSGOM), it was 12 nm. Additionally, TCSCM had a thinner layer at only 1.10 µm, while TCSGOM was slightly thicker at 2.11 µm. These features influenced the permeate flux of the membrane, in which the TCSGOM exhibited lower permeate flux (18.2 L·m−2·h−1) than the TCSCM (45.6 L·m−2·h−1). However, the anaerobic decolorization results indicated that the TCSGOM bioreactor (B-TCSGOM) was more efficient and effective at removing color from all dye solutions than the TCSCM bioreactor (B-TCSCM) over a wide range of feed concentrations. In both reactors, the highest decolorization was achieved at low feed concentration (50 mg·L−1), and removal was 94 % for AO7, 90 % for RB5, and 88 % for DB71 in B-TCSGOM, whereas 88 %, 85 %, and 69 %, respectively, in B-TCSCM. These suggest that the robust conductive nanoporous surface of B-TCSGOM makes it more effective at removing different azo dye solutions from wastewater.