Photocatalytic Membrane Reactor Research Articles

Characterization and performance evaluation of in-house ultrafiltration membrane coupled with photocatalysis for 17α-methyltestosterone hormone removal.

17α-methyltestosterone (MT) hormone is a synthetic androgenic steroid hormone utilized to induce Nile tilapia transitioning for enhanced production yield. This study specifically focuses on the removal of MT through the utilization of photocatalytic membrane reactor (PMR), which employs an in-house polyvinylidene fluoride (PVDF) ultrafiltration membrane modified with 1% nanomaterials (either TiO2 or α-Fe2O3). The molecular weight cut-off (MWCO) of the in-house membrane falls within the ultrafiltration range. Under UV95W radiation, the PMR with PVDF/TiO2 and PVDF/α-Fe2O3 membranes achieved 100% MT removal at 140 and 160 min, respectively. The MT removal by the commercial NF03 membrane was only at 50%. In contrast, without light irradiation, the MT removal by all the membranes remained unchanged after 180 min, exhibiting lower performance. The incorporation of TiO2 and α-Fe2O3 enhanced water flux and MT removal of the membrane. Notably, the catalytic activity was limited by the distribution and concentration of the catalyst at the membrane surface. The water contact angle did not correlate with the water flux for the composited membrane. The degradation of MT aligned well with Pseudo-first-order kinetic models. Thus, the in-house ultrafiltration PMR demonstrated superior removal efficiency and lower operational costs than the commercial nanofiltration membrane, attributable to its photocatalytic activities.

Tetracycline degradation through selective activation of molecular oxygen by a fluidic sequential photoelectro-Fenton system

The heterogeneous Fenton-like process is regarded as a promising strategy for reactive oxygen species (ROS) production by driving a two-electron oxygen reduction reaction toward H2O2 and stepping activating the as-generated H2O2 to ROS. Therefore, a fluidic sequential photoelectro-Fenton (PEF) system was developed for the selective activation of molecular oxygen to generate ROS. The system comprises a hydrogen peroxide (H2O2) electrolyzer and a photocatalytic membrane reactor (PCMR). The H2O2 electrolyzer employed a PEI-O/CNT air self-diffusion electrode to achieve high selectivity for H2O2 production without aeration. In the subsequent stage, within the PCMR, two-dimensional Fe/C3N4 with a nanoconfinement structure selectively converted H2O2 into ROS. The exceptional tetracycline (TC) degradation efficiency (96.0 %) was attributable to the synergistic effects of radical and non-radical pathways. The fluidic sequential PEF system achieved efficient and energy-saving H2O2 production (0.134 kWh/g of H2O2) and TC degradation (1.7 kWh/kg of TC). In addition, the PEF system not only has a good effect on removing tetracycline in real water but also can effectively remove a variety of antibiotic pollutants, which has a good prospect for practical application. This research contributed new insights into the development of the fluidic sequential PEF process.

Palm oil mill secondary effluent treatment using ZNO-clay liquid photocatalyst in membrane photocatalytic reactor

In recent years, photocatalytic treatment of palm oil mill secondary mill effluent (POMSE) incorporating ZnO nanoparticles with various types of capping agents via membrane photocatalytic reactor (MPR) has gained great interest among researchers. Nevertheless, most of previous studies have employed a rather time-consuming oven drying and calcination method to synthesise ZnO in powder form. Therefore, a simpler synthesis method is considered necessary. In this study, ZnO-clay was synthesised in liquid form using the precipitation method, without undergoing oven drying and calcination. The effect of different ZnO-clay ratios on the degradation performance of POMSE via MPR was also examined. Results indicated that ZnO-clay 1:3 was efficient in BOD removal percentage, while the removal percentages of COD, colour and turbidity were higher for ZnO-clay 1:5 compared to other ratios.

Optimization of photocatalytic ceramic membrane filtration by response surface methodology: Effects of hydrodynamic conditions on organic fouling and removal efficiency

The effects of the operating conditions, including the applied pressure, feed organic concentration, and recirculation flowrate along the TiO2-coated ceramic membrane, on the normalized membrane permeability and organic removal efficiency were systematically investigated by operating a photocatalytic membrane reactor (PMR). Response surface methodology (RSM) was conducted to better understand the interactive effect of operational conditions as well as their individual and combined effects to control membrane performance. Our results showed that the applied pressure and feed organic concentration, as single parameter, affected the normalized membrane permeability and organic removal efficiency more dominantly than the recirculation flowrate. The polynomial performance equations generated by RSM successfully predicted the membrane performance of the PMR. The responses to the normalized membrane permeability and organic removal efficiency with respect to the operational conditions were less sensitive to any combination of operational conditions than to their individual impacts. The combined effects of the operating conditions were less pronounced in promoting the catalytic performance of organic contaminants on the TiO2 surface. Our RSM analysis based on experimental observations designed by Box–Behnken Design (BBD) suggested that 1.3 bar of applied pressure, 44 mg/L of feed organic dye concentration and 0.8 L/min as recirculation flowrate as optimum conditions achieved more than 98% of organic removal efficiency and less than 5% of decline in normalized membrane permeability. This research shows that the RSM provides effective tool to optimize operational conditions to determine fouling rate and organic removal in PMR.

Performance of a Solar-Driven Photocatalytic Membrane Reactor for Municipal Wastewater Treatment

The increasing demand for efficient wastewater treatment technologies, driven by global population growth and industrialisation, highlights the necessity for advanced, reliable solutions. This study investigated the efficacy of a slurry photocatalytic membrane reactor (PMR) for the advanced removal of organic pollutants, quantified via chemical oxygen demand (COD), under natural and simulated solar light irradiation. Employing two variants of iron-doped titania as photocatalysts and a polysulfone-based polymeric membrane for the separation process, the investigation showcased COD removal efficiencies ranging from 66–85% under simulated solar light to 52–81% under natural sunlight over a 7 h irradiation period. The overall PMR system demonstrated COD removal efficiencies of 84–95%. The results confirmed the enhanced photocatalytic activity afforded by iron doping and establish solar-powered slurry PMRs as an effective, low-energy, and environmentally friendly alternative for the advanced treatment of municipal wastewater, with the research providing valuable insights into sustainable water management practices.

Preparation of mixed matrix self-cleaning membrane incorporated by Z-scheme heterostructure via robust engineering in terms of dimension for decreasing cake fouling in a cross-flow reactor

Reducing irreversible fouling in polymer membranes by integrating photocatalytic and membrane processes as the self-cleaning photocatalytic membrane is a promising candidate for improving membrane filtration performance. In this study, mixed matrix photocatalytic membranes were prepared from the combination of different morphologies ZnO-g-C3N4 heterostructure in the polymer matrix by the phase-separation method. To investigate the self-cleaning and performance properties of mixed matrix photocatalytic membranes prepared from different morphologies heterostructures, the photocatalytic membrane reactor with a visible-light source was applied. Nanoflower/nanosheet (NF/NS) ZnO-g-C3N4 photocatalytic membrane showed good self-cleaning performance owing to the high photocatalytic performance of NF/NS ZnO-g-C3N4 heterostructure by the reduction of irreversible membrane fouling, thus improving the antifouling and filtration performance of the membrane. Also, the morphology and the uniform distribution of the NF/NS ZnO-g-C3N4 heterostructure in the membrane matrix caused good hydrophilic properties, high porosity, and a more symmetrical structure in the (NF/NS) ZnO-g-C3N4 photocatalytic membrane (F4). For the F4 membrane, the permeability and rejection values increased from 40.35 L m−2 h−1 and 90.9% in the dark environment to 84.37 L m−2 h−1 and 97.4% under visible-light for dye pollutants. Accordingly, F4 had the best filtration and self-cleaning performance, which can be used as a promising visible-light photocatalytic membrane in wastewater treatment processes.

Application of a submerged photocatalytic membrane reactor with ultrafiltration membrane for ketoprofen removal during long term process: Impact of feed matrix

The research was focused on the evaluation of a long-term performance of a submerged photocatalytic membrane reactor utilizing ultrafiltration (SPMR-UF) operated in a continuous mode for removal of ketoprofen from various synthetic aqueous feeds (brackish, surface, seawater and secondary effluent of a wastewater treatment plant). The highest initial rate of ketoprofen degradation was found for brackish water. Nonetheless, after 24 h of the SPMR-UF operation the removal rate of the drug was similar for all feed types (93–96 %). The selected process parameters (suction pressure of −0.01 MPa and backflush frequency of 1 min: 30 min) allowed to realize the process without any permeate flux decline when brackish and seawater were applied. However, fouling was observed in the case of surface water and secondary effluent, mainly due to the presence of humic acids or peptone and meat extract in the feed. Autopsy of the membrane revealed CaSO4 and CaCO3 crystals on the TiO2 layer covering the membrane surface after treatment of brackish water, seawater and secondary effluent, indicating the important role of the photocatalyst in UF membrane scaling. It was concluded that since the main process determining the efficiency of SPMR-UF is photocatalysis, its optimization is of high importance.

Tetracycline removal from wastewater via g-C3N4 loaded RSM-CCD-optimised hybrid photocatalytic membrane reactor

In this study, a split-type photocatalytic membrane reactor (PMR), incorporating suspended graphitic carbon nitride (g-C3N4) as photocatalyst and a layered polymeric composite (using polyamide, polyethersulfone and polysulfone polymers) as a membrane was fabricated to remove tetracycline (TC) from aqueous solutions as the world's second most used and discharged antibiotic in wastewater. The photocatalyst was synthesised from melamine by ultrasonic-assisted thermal polymerisation method and, along with the membrane, was characterised using various methods, including Brunauer–Emmett–Teller analysis (BET), Fourier-transform infrared spectroscopy (FTIR), X-ray diffraction analysis (XRD), Field emission scanning electron microscopy (FESEM), and Ultraviolet–visible spectroscopy (UV–Vis). The PMR process was optimised, using Design-Expert software for tetracycline removal in terms of UV irradiation time, pH, photocatalyst loading, tetracycline concentration, and membrane separation iteration. It was revealed that a membrane-integrated reactor as a sustainable system could effectively produce clean water by simultaneous removal of tetracycline and photocatalyst from aqueous solution. The maximum removal of 94.8% was obtained at the tetracycline concentration of 22.16 ppm, pH of 9.78 with 0.56 g/L of photocatalyst in the irradiation time of 113.77 min after six times of passing membrane. The PMR system showed reasonable reusability by about a 25.8% drop in TC removal efficiency after seven cycles at optimal conditions. The outcomes demonstrate the promising performance of the proposed PMR system in tetracycline removal from water and suggest that it can be scaled as an effective approach for a sustainable supply of antibiotic-free clean water.

Highly Active 3D Composites for a Flow-Through Photocatalytic Membrane Reactor toward Water Micropollutant Removal

Highly Active 3D Composites for a Flow-Through Photocatalytic Membrane Reactor toward Water Micropollutant Removal

The Performance of ZnO-Lemongrass in Photocatalytic Membrane Reactor (PMR) for Palm Oil Mill Second Effluent (POMSE)

The nation that produces and exports the greatest amount of palm oil is Malaysia. As the palm oil business expands, so does pollution from palm oil mill second effluent (POMSE) in the country. The photocatalytic membrane reactor (PMR) has demonstrated a significant potential to develop into a "zero" waste process in the water or wastewater sector. The aim of the research is to elucidate the performance of zinc oxide (ZnO) nanoparticles with lemongrass (ZnO-L) as a capping agent in photocatalytic and PMR applications for treating POMSE. The POMSE samples were added to the reactor in the PMR with a pH of 9 and 0.1 g/L of ZnO-L loading. The POMSE pollutant may be degraded in the photocatalytic process during the process, and then the nanoparticles and POMSE pollutants was separated from the effluent through membrane process. The research findings indicate that the ZnO-L 3 from PMR has a greater proportion of colour removal than the photocatalytic only, which is 99.85%. This demonstrates that PMR is superior to the photocatalytic technique. Following that, the ZnO-L 3 had the lowest flux drop (67%), causing reduction of membrane fouling owing to more degradation of pollutants. Therefore, the ZnO-L performance was successfully evaluated, demonstrating that PMR outperforms photocatalytic processes in terms of colour intensity.

Remediation of groundwater pollution using photocatalytic membrane reactors

Recalcitrant pollutants in groundwater and industrial wastewater streams are very dangerous for the environment and human health. The conventional water treatment processes are not capable to degrade/removing them due to their very high chemical stability. The photocatalytic membrane reactors represent a possible route for overcoming the limits present in the conventional ones. In this study, photocatalyst loaded mixed matrix membranes (PMMM) were prepared using non solvent induced phase inversion process and titanium dioxide as a photocatalyst. SEM and EDX analyses, contact angle, and tensile strength measurements were used for characterizing the membranes. Their catalytic activity was assessed using the methyl orange as a recalcitrant pollutant. The photoactivity of the PMM membranes increased with the TiO2 content. The membrane loaded with the 2.5 wt % of titanium dioxide achieved better degradation and retained high degradation efficiency after 4 cycles, indicating the stability of the membrane.

MECHANISM OF MEMBRANE FOULING IN HYBRID MEMBRANE PHOTOCATALYTIC REACTOR FOR PALM OIL MILL SECONDARY EFFLUENT TREATMENT

Palm oil mill secondary effluent (POMSE) is a byproduct of the biological treatment of palm oil mill effluent. This research aims to investigate the mechanism of membrane fouling in the treatment of POMSE using a hybrid membrane photocatalytic reactor (MPR). The effectiveness of MPR in POMSE treatment is currently limited due to membrane fouling on the membrane surface. This study focuses on understanding the various mechanisms of membrane fouling, including complete blocking, intermediate blocking, standard blocking, and cake filtration. The determination of each fouling mechanism is achieved through an analysis of normalized flux data employing the Wiesner and Aptel equation. The results demonstrate a high degree of model fitness (R2 = 0.9576) for MPR Run 3, confirming its effectiveness. Based on the (R2) values and the fitted parameter (Ks^(-1)), it is evident that, under varying pH levels, catalyst types, catalyst loading, and initial POMSE concentrations, the cake formation fouling mechanism prevails in MPR Run. In conclusion, this research holds promising potential for implementation in the wastewater treatment industry while ensuring compliance with environmental regulations.

A study on photocatalytic Janus membrane reactor for direct conversion of low concentration carbon dioxide in air to methane: Effects of combination of two-dimensional carbon nanosheets

Large CO2 emissions cause the greenhouse effect, which threatens human survival. Directly converting CO2 in the air into energy and valuable resources is the most effective way to address the greenhouse effect. Currently, the main problem with CO2 conversion is the poor conversion efficiency owing to low CO2 concentrations in the air. In this study, a Janus membrane with the functions of concentrating CO2 (gas separation layer) and photocatalytic reaction (photocatalytic reaction layer) was fabricated. The Janus membrane directly converted extremely low concentrations of CO2 in the air into CH4. Amine-functionalized graphene oxide was added to regulate the CO2 conversion efficiency and the structure of the gas separation layer. Graphene was added to the photocatalytic reaction layer to suppress electron-hole recombination and increase the probability of excited electrons colliding with CO2. The experimental results showed that the modification of the gas separation layer or the photocatalytic reaction layer effectively increased the CH4 yield of the Janus membrane. By maintaining a balance between the selectivity and permeability coefficients of the gas separation layer, the highest methane yield (8.9 ppm) was obtained. The CH4 yield of the Janus membrane was further improved (8.9 ppm to 11.1 ppm) by modifying the photocatalytic reaction layer with graphene. This study proposes a feasible method for improving the efficiency of the Janus membrane for converting low-concentration CO2 in air to CH4.

Breaking down process barriers: ZnSe/CdSe composite catalysts drive enhanced catalytic properties and modified membrane structures for removing humic acid from aqueous environments

In the present research, with the aim of removing humic acid from wastewater, photo-catalytic membrane reactor was utilized. Single-component catalysts including ZnSe, CdSe, as well as composite catalyst (ZnSe/CdSe) were deposited in the surface layer of polysulfone membrane via photo-grafting method, whereby ZniCdjM11i and j are ZnSe and CdSe loading concentration level membranes were synthesized. The results indicated that the ZnSe/CdSe due to its shorter bandgap, had a more effective role in the grafting process and hence adjusting the membrane pore size. The pore size of Zn4Cd4M was smaller than that of Zn4Cd0M and Zn°Cd4M, and hence the humic acid separation in the dark mode by Zn4Cd4M was 80 %, which is about 10 % greater than the value obtained by Zn4Cd0M and Zn°Cd4M. The ZnSe/CdSe due to its less photoluminescence emission, proved to be more effective in photocatalytic reactions compared to the single component catalysts. The extent of photocatalytic degradation of humic acid in the presence of UV-radiation by the Zn°Cd4M, Zn4Cd0M, and Zn4Cd4M was reported 80, 84, and 96 % respectively. Overall, due to the smaller pore size, shorter bandgap, and lower recombination, TOC removal by the Zn4Cd4M (containing composite catalyst) was reported 98 %, while this value for the Zn4Cd0M and Zn°Cd4M was reported 60 and 66 % respectively.

Photocatalytic and antimicrobial efficacy of PVDF/TiO2 membranes fabricated by solution blow spinning

AbstractWith its ability to purify water and treat wastewater, photocatalytic membranes have become a promising solution. The membrane's unique properties allow for the separation of solid compounds and the degradation of organic materials through photocatalytic and antibacterial means. Poly(vinylidene fluoride)/titanium oxide (PVDF/TiO2) composite remain the materials of choice for making these membranes due to their economy, effectiveness, safety, and durability. In this work a photocatalytic membrane reactor (PMR) system was developed using PVDF/TiO2 membranes fabricated by the solution blow spinning (SBS) process. Obtaining photocatalytic membranes using this method is an efficient and ecological route that overcomes the disadvantage of separating the photocatalyst after the treatment is complete. The results of PMR system showed that the PVDF/TiO2 membrane could effectively remove total coliforms and E. coli from polluted water. After 10 min of contaminated water circulation through the PMR system, the presence of pathogens was not detected, indicating the efficiency of the obtained membranes.

CFD-Assisted Process Optimization of an Integrated Photocatalytic Membrane System for Water Treatment.

An integrated photocatalytic membrane system (IPMS) was developed for potential use in the remediation of naproxen using real water samples from a drinking water treatment plant. Key parameters such as time, pH, water matrix, mixing speeds, flow rate, and light intensity undeniably affected photocatalytic and membrane separation processes. The system optimization was based on improving irradiation to generate a more reactive species and mass transfer to increase the reaction rate. Upon optimization, IPMS achieved 99% naproxen removal efficiency. Computational fluid dynamics (CFD) simulated the flow patterns and radiation distribution inside the photocatalytic membrane reactor to improve irradiation and mass transfer during operation. The simulated flow field revealed the presence of dead zones with different velocities in the photocatalytic membrane reactor; this limited the mass transfer of reactive species in the reactor, resulting in uneven distribution of reactive radicals. The dead zones were mitigated by increasing the mixing speed, and as a result, convective mass flow improved process performance. The governing parameters (flow patterns and radiation distribution) of the simulated and experimental data were in agreement. The absorption of irradiation by the active site of the membranes improved with light intensity; at higher light intensities, the light irradiated deeper into the membrane. As such, the CoFe2O4 nanoparticles incorporated inside the membrane pores became highly activated, thus enhancing degradation. The obtained space-time yield (STY) (1.23 × 1011 mol/cm2.s) and photocatalytic space-time yield (PSTY) (4.39 × 1011 mol/W.s) showed that the developed IPMS was efficient regarding energy intensiveness and throughput for treatment of pollutants in water.

Hydrodynamics and Energy Analysis in Suspended Catalyst Photocatalytic Membrane Reactors

Photocatalysis is a non-selective advanced oxidation process (AOP) that can be effective for degradation of toxic compounds. Its main drawback however has been high processing costs compared to other AOPs. Suspended catalyst photocatalytic membrane reactors (SPMR) are promising design configuration for implementation of the technology. This work involves experimental and theoretically analysis of the hydrodynamics and energy consumption in a SPMR under crossflow and oscillatory shear conditions. An optimization approach is presented for intensification of the reactor performance that considers the coupling effects of the applied shear and the transmembrane pressure on the hydrodynamics and the specific energy consumption (kWh/m3). The results showed that the optimum shear rate decreases with increasing the membrane area due to the relatively high contribution of the permeate pumping power to the energy consumption which makes the advantages of operating at higher shear rate relevant. This trend changes for larger membranes areas where the energy consumption due to higher shear outweighs the advantage of its performance enhancement resulting in increasing the system specific energy consumption. In general, the latter was found to be higher for a crossflow system compared to an oscillatory membrane design, which in addition to its smaller footprints, can make such design an attractive option for confined and/or limited space applications.

Processing of membranes and 3D scaffolds based on n-TiO2 colloidally dispersed on a thermoplastic matrix for photocatalytic pollutant removal

One of the most promising technologies for water treatment today is photocatalytic membrane reactors (PMRs). Manufacturing efficient membranes is still challenging as many factors are involved, like the porosity, specific surface area, nature and size of particles. In this work, a colloidal method to self-support commercial nanoparticles (n-TiO2) in a polymeric matrix of polylactic acid (PLA) is proposed allowing the fabrication of 2D and 3D structures with high inorganic content that can be adapted to the PMR configurations. Using a commercial filament of PLA loaded with up to 15 vol% of n-TiO2 as starting point, photocatalytic membranes have been manufactured by FFF. In addition, following a similar process, tapes with n-TiO2 particles up to 15 vol% have been processed by tape casting. Thermal characterisation (DTA) and dynamic rheometry evaluated the commercial filament for printing to determine the conditions used during the thermal extrusion and printing processes. FTIR and XRD technologies were used to determine the chemical interactions of PLA matrices with TiO2 nanoparticles. Porosity was measured by Archimedes's method for the filaments, by mercury intrusion for the membranes and by optical microscopy for the scaffolds. Finally, the microstructure of the 2D and 3D pieces was evaluated by scanning microscopy. 2D tape cast membranes were compared with individual filaments and 3D printed scaffolds in linear and gyroidal geometries. The catalytic activity results indicate that tape cast membranes show much higher kinetic constants than the individual filaments and the linear and gyroidal scaffolds. Regarding the two different printed scaffolds, in contrast to the kinetic values, gyroidal geometries achieve an average degradation time (t50) of 6.1 h, which is a lower value than those observed for linear scaffold geometries. Methyl orange degradation tests after 24 h exposure under UV light showed degradation rates of 98% for membranes, 90% for commercial filaments, 80% for gyroidal scaffolds and 60% for linear patterns. Therefore, these results are promising as a solution for fabricating easily extractable self-supported membranes for water treatment in PMRs.

Which Configuration of Photocatalytic Membrane Reactors Has a Major Potential to Be Used at an Industrial Level in Tertiary Sewage Wastewater Treatment?

Photocatalytic membrane reactors (PMRs) have been found to be very effective in the removal of organic pollutants (particularly recalcitrant compounds) from wastewater because they allow for the mineralization of organic pollutants to innocuous by-products, thus achieving high-quality treated water. Owing to the very high volumes of water involved, treated sewage wastewater could be reused if a very efficient tertiary stage, like a PMR, can be foreseen. In this review, the two main PMR configurations (photocatalytic membranes and slurry PMRs) were analyzed as requirements of a tertiary treatment of sewage wastewater considering six design and operational parameters of such plants: (i) continuous wastewater flow rate from the secondary stage; (ii) the self-control of the photodegradation rate related to wastewater chemical–physical parameters; (iii) ability to handle variations of wastewater concentration and flow rate; (iv) the control of the quality of treated wastewater; (v) low plant footprint; and (vi) easy maintenance. In this analysis, some characteristics of photocatalysis (which involves three phases: solid (the photocatalyst), liquid (the wastewater), and gas (oxygen or air)) and those of membranes (they can be produced using different materials and configurations, different processes (pressure-driven or not pressure-driven), etc.) were considered. The obtained results show that slurry PMRs seem more suitable than photocatalytic membranes for such applications. We believe this review can trigger a shift in research from the laboratory to industry in using photocatalytic membrane reactors.

Influence of organic matter on the photocatalytic degradation of steroid hormones by TiO2-coated polyethersulfone microfiltration membrane

Water treatment in photocatalytic membrane reactors (PMR) holds great promise for removing micropollutants from aquatic environments. Organic matter (OM) that is present in any water matrix may significantly interfere with the degradation of steroid hormone (SH) micropollutants in PMRs. In this study, the interference of various OM types, humic acid (HA), Australian natural organic matter (AUS), worm farm extract (WF), tannic acid (TA), and gallic acid (GA) with the SH degradation at its environmentally relevant concentration (100 ng/L) in a flow-through PMR equipped with a polyethersulphone-titanium dioxide (PES-TiO2) membrane operated under UV light (365 nm) was investigated. Results of this study showed that OM effects are complex and depend on OM type and concentration. The removal of β-estradiol (E2) was enhanced by HA at its levels below 5 mgC/L while the enhancement was abated at higher HA concentrations. The E2 removal was inhibited by TA, and GA, while no significant interference observed for AUS, and WF. The data demonstrated diverse roles of OM that acts in PMRs as a light screening agent, a photoreactive species scavenger, an adsorption alteration trigger, and a photosensitizer. The time-resolved fluorescence measurement showed that HA, acting as a photosensitizer, promoted the sensitization of TiO2 by absorbing light energy and transferring energy/electron to the TiO2 substrate. This pathway dominated the mechanism of the enhanced E2 degradation by HA. The favorable effect of HA was augmented as increasing the light intensity from 0.5 to 10 mW/cm2 and was weakened at higher light intensities due to the increased scavenging reactions and the limited amount of HA. This work clarifies the underlying mechanism of the OM interference on photocatalytic degradation of E2 by the PES-TiO2 PMR.