Removal Experiments Research Articles

Contributions of Perennial Pepperweed (Lepidium latifolium) Invasion to Rarity of the Endangered Suisun Thistle (Cirsium hydrophilum var. hydrophilum)

Invasive species exert disproportionate impacts in wetlands and pose particular challenges for rare species persisting at small spatial scales. In the urbanized San Francisco Estuary (SFE), which contains 90% of California’s remaining coastal wetlands, invasive and rare species often co-occur. One narrow endemic taxon, the federally listed Suisun thistle (Cirsium hydrophilum var. hydrophilum) is restricted to two or three locations where the invasive perennial pepperweed (Lepidium latifolium) has an increasing presence. Perennial pepperweed has invaded salt, brackish, and freshwater wetlands around the SFE, leading to high management concern. In this study, we investigated how perennial pepperweed may contribute to further rarity of the Suisun thistle, by conducting a removal experiment and surveying soil-plant relationships. Removing pepperweed led to a doubling of native species relative cover and an increase in native species richness by an average of one species per plot, positive effects on Suisun thistle cover, number, and reproductive output, and shifts in soil properties. Combined with survey data inside and outside of pepperweed stands, we conclude that pepperweed competes with Suisun thistle via competition for space, nutrients, and light, interferes with the Suisun thistle’s reproductive success, and alters brackish marsh soil physicochemical characteristics to further favor pepperweed. We recommend local control of pepperweed to prevent further loss of Suisun thistle. Further, the wide range of mechanisms by which this invasion may proceed if unchecked should be considered in other settings where rare or uncommon species are at risk from invaders.

Construction of site-specific magnetic Z-scheme CdS/Fe3O4@N-doped graphene aerogel microtube/N-doped TiO2 with porous structure: enhanced catalytic performance in photo-Fenton reaction.

The development of composite photocatalysts with high charge transfer efficiency, great visible light absorption, and quick recovery has aroused the interest of many researchers. Herein, based on the hydrothermal assisted vacuum freeze drying method, CdS, Fe3O4, and N-TiO2 were, respectively, fixed in the inner, middle, and outer layers of nitrogen-doped graphene aerogel for preparation of the site-specific magnetic porous Z-scheme CdS/Fe3O4@N-doped graphene aerogel microtube/N-doped TiO2 (CdS/Fe3O4@NGAM/N-TiO2) photocatalyst. For the composite, Fe3O4@NGAM carrier with porous and tubular structure not only helps the recycle and reactants/productions mass transport in the photocatalytic process but also ensures the well-steered transfer of electrons and holes from CdS and N-TiO2 in the Z-type heterojunction system, greatly improving the separation of photogenerated carriers. Besides, Fe3O4 can also work as a Fenton catalyst to activate hydrogen peroxide which is generated in situ by CdS. Thus, the CdS/Fe3O4@NGAM/N-TiO2 composite presents excellent degradation efficiencies towards methyl orange ((MO) 98% removal rate within 50min), bisphenol A ((BPA) 96% removal rate within 50min), tetracycline hydrochloride ((TCH) 96% removal rate within 120min) and strong stabilities after 6 cycles. The free radical removal experiments show that ·O2- and ·OH are the main active substances of catalysis, which further confirms the synergistic effect of photocatalysis and Fenton catalysis.

Study on the Catalytic Oxidation of Toluene Using CeO2@S-AZMB Prepared from Spent Zn-Mn Batteries

The recycling and utilization of waste alkaline zinc manganese batteries (S-AZMB) has always been a focus of attention in the fields of environment and energy. However, current research mostly focuses on the recycling of purified materials, while neglecting the direct reuse of waste batteries. Here, we propose a new concept of preparing thermal catalysts by combining unpurified S-AZMB with CeO2 by means of ball milling. A series of characterizations and experiments have confirmed that the combination with S-AZMB not only enhances the thermal catalytic activity of CeO2 but also significantly enhances the concentration of surface oxygen vacancies. In the toluene removal experiment, the temperature (T90) at 90% toluene conversions of CeO2@S-AZMB was 180 °C, lower than the 220 °C for CeO2. More noteworthy is that this S-AZMB-based thermal catalyst can maintain a good structure and thermal catalytic stability in cyclic catalysis.

Assessing impacts of a notorious invader (common carp Cyprinus carpio) on Australia's aquatic ecosystems: Coupling abundance-impact relationships with a spatial biomass model

Quantifying the ecological impacts of non-native species is essential for large scale conservation management. Estimating such impacts often require spatially explicit abundance(/biomass) models of the target non-native species and knowledge of abundance-impact relationships, both of which are rarely known. Common carp (Cyprinus carpio) is a major threat to aquatic systems globally and relatively well-studied but yet models quantifying landscape-scale impacts of carp invasions are lacking. Here, we undertake a nonlinear meta-analytic approach to describe biomass-impact relationships for eight impact metrics and then integrate these relationships with a recently published spatial carp biomass model for Australia in order to quantify the ecological impacts of the carp invasion on Australian aquatic ecosystems. For the meta-analysis we collated 286 abundance(biomass)-impact estimates from 41 studies. Our meta-analysis identified both linear and nonlinear biomass-impact relationships across the impact metrics. Using a small, out-of-sample validation from carp removal experiments, the model had high prediction accuracy (within <20 % of estimate) for four metrics, but one metric (macrophyte recovery) was consistently underestimated by 10 to 35 %. Finally, we estimated that the carp invasion in Australia has resulted in decreases in macrophytes (median of −36 %) and macroinvertebrates (−31 %) and increases in nitrogen (2 %), plankton biomass (7 %), phosphorus (8 %) and turbidity (63 %). The invasive spread of carp has fundamentally altered Australia's aquatic environments and this study provides the first quantitative assessment of this impact and a tool to guide carp management decisions.

Synergetic Adsorption of Dyes in Water by Three-Dimensional Graphene and Manganese Dioxide (PU@RGO@MnO2) Structures for Efficient Wastewater Purification

The improper discharge of industrial wastewater causes severe environmental pollution and the textile industry’s dye usage contributes significantly to industrial wastewater pollution. Hence, an effective method for removing the harmful substance methylene blue (MB) from dye wastewater is proposed. This method adopts a three-dimensional graphene composite material based on manganese dioxide (MnO2), named polyurethane@ reduced graphene oxide@ MnO2 (PU@RGO@MnO2). First, graphene is prepared with hydrazine hydrate as a reducing agent and polyurethane as a framework. MnO2 nanoparticles are synthesized by the reaction of potassium permanganate (KMnO4) with carbon. These nanoparticles are then loaded onto the three-dimensional framework to create the composite material. Finally, adsorption and removal experiments for MB are conducted to compare the performance of the composite material. The results indicate that the graphene based on the polyurethane framework exhibits favorable mechanical properties. The unique three-dimensional lattice structure provides abundant active sites for loading MnO2 nanoparticles, significantly increasing the contact area between the adsorbent and MB solution and thus improving the adsorbent utilization rate (reaching 94%). The nanoparticles synthesized through the reaction of KMnO4 with carbon effectively suppress the agglomeration phenomenon. Additionally, the introduction of dynamic adsorption and dynamic removal modes, aided by a water pump, substantially enhances the adsorption and removal rates, showcasing excellent performance. The research on a multi-porous three-dimensional structure holds significant practical value in water treatment, offering a new research direction for dye wastewater treatment.

Micropore system properties significantly influence the Na-type zeolite adsorption of the carbon disulfide impurity in mimetic coke oven gas

The experiments of the adsorption removal of CS2 impurity from a mimetic coke oven gas were performed by using a series of Na-type zeolites as adsorbents. Combining with the diffusion & simulation calculations and several characterizations, it's found both the development degree and the diffusion ability of microporous systems significantly influence the adsorption performance of these Na-type zeolites on which the physical absorption was predominant for CS2 molecules. Firstly, compared with NaZSM-5 or NaSAPO-34, the NaY with FAU-type framework exhibited a much higher breakthrough adsorption capacity, primarily due to its much higher microporous surface area & volume and larger-size channels, which ensured a broader adsorption space, a high-efficiency molecule-diffusion and a high adsorption utilization of micropores. Secondly, alkali-treatment introduced some mesopores into NaZSM-5 crystals but also resulted in a declined integrity of microporous structure, causing an obvious decline of adsorption performance. Thirdly, the nano-crystal NaZSM-5 or NaY exhibited a much higher breakthrough adsorption capacity than that of the corresponding micron-crystal zeolite, primarily attributed to both the increased microporous surface area & volume and the shortened micropore diffusion-path length of the former. In addition, a breakthrough adsorption capacity of up to 0.251 g/g was obtained in the first adsorption use of a nano-NaY-0.909 sample at 298 K, and it's 0.229 g/g in even the sixteenth time of operation (by then, total adsorption service hours were 80.58 h). Our work may provide an important reference for developing high-performance adsorbents for removing gaseous CS2 impurity in coke oven gas.

Bisphenol A (BPA) remediation using walnut shell as activated carbon employing experimental design for parameter optimization and theoretical study to establish the adsorption mechanism

Carbon-based materials have garnered significant attention as highly efficient adsorbents for wastewater treatment, owing to their cost-effectiveness and remarkable stability. In this research, activated carbon derived from biomass, specifically agricultural waste, emerges as a promising choice for the adsorption of organic pollutants. Various characterization techniques, including XRD, FTIR, SEM/EDX, pHzpc, and Boehm titration, were employed to delineate the distinctive features of our activated carbon (AC-Ws). Furthermore, Response Surface Methodology (RSM) was utilized to scrutinize the interplay of bisphenol A (BPA) concentration, pH, AC-Ws mass, and temperature on BPA uptake. Under optimal conditions, a remarkable 97.47 % efficiency in BPA removal was achieved. Thermodynamic analysis revealed the favorable and endothermic nature of the adsorption process. The pseudo-second-order kinetic model accurately described the experimental data, while the Langmuir isotherm model aptly captured the equilibrium data, disclosing a maximum BPA adsorption capacity on AC-Ws of 238.63 mg/g. To evaluate the reusability of the AC-Ws adsorbent, five cycles of pollutant removal experiments were conducted. Moreover, the adsorption mechanism on AC-Ws surface sites was explored using Density Functional Theory (DFT).

Resilience of Amazon rainfall to CO2 removal forcing

Over the Amazon region, rainfall-induced changes to CO2 pathways significantly impact humans and multiple ecosystems. Its resilience is of vital importance, and idealized CO2 removal experiments indicate that declining trends in rainfall amounts are irreversible and exhibit a deficiency when the CO2 concentration returns to the pre-industrial level. The irreversible decline in Amazon rainfall is mainly due to the weakened ascent, further led by two main causes. (1) Enhanced tropospheric warming and a wetter atmospheric boundary layer over the tropics during CO2 removal generate a strong meridional gradient of temperature and specific humidity; driven by prevailing northeasterly winds, negative moist enthalpy advection occurs, which in turn weakens the ascent over the Amazon and results in anomalous drought. (2) The enhanced radiative cooling of atmospheric column. Driven by the negative lapse-rate feedback, the outgoing longwave radiative flux increases in the clear-sky atmosphere. As a result, the anomalous diabatic descent generates to maintain the energy balance of the atmospheric column. This result implies that the symmetric removal of CO2 does not guarantee full recovery of regional precipitation.

Monitoring lianas from space: Using Sentinel-2 imagery to observe liana removal in logged tropical forests

Liana removal – the cutting of over-abundant woody climbing plants (lianas) – has the potential to substantially increase tree growth and biomass accumulation across millions of hectares of degraded tropical forest. Satellite imagery could provide data capable of observing the effect of liana removal on the forest canopy, enabling the large-scale monitoring and validation of liana removal, which remains a key hurdle to its widespread implementation. Using a 320-ha liana removal experiment in Sabah, Malaysian Borneo, we tested whether a time series of Sentinel-2 images could observe the canopy signature of liana removal. Calculating a range of metrics derived from the Normalized Burn Ratio – a vegetation index based on spectral reflectance that differentiates leaf from non-leaf – we quantified satellite-derived canopy disturbance and fragmentation across a range of liana removal intensities and examined how canopy disturbance changed in the 12-months following removal treatments. We find that liana removal significantly increases canopy disturbance and fragmentation metrics one month after removal, with partial removal having a smaller effect than complete removal. The impact of liana removal on the canopy metrics declined over time, with measures of canopy disturbance and fragmentation largely indistinguishable from control forest within 12-months of treatment. Our findings evidence that freely available satellite imagery can be used to efficiently monitor large-scale liana removal applied at a range of intensities and suggest that partial liana removal could significantly reduce canopy disturbance of this restoration method.

Generative adversarial networks for rubber stamp extraction and removal

Due to the variety of documents and people's different stamping habits, it is difficult for current models to achieve satisfactory results in the process of extracting and removing rubber stamps. Most current methods cannot extract or remove rubber stamps without destroying the background text information. To solve the above problems, we propose a neural network that uses a double-cycle structure, named stamp extraction and removal generative adversarial network (SERGAN). In detail, we improve SERGAN's cycle-consistency by simultaneously recombining the generated rubber stamp image and unstamped image into a stamped image, which enables SERGAN to have multi-domain image conversion capability. To prove the model's generalization ability, we compare it with current mainstream methods on the public watermark dataset CLWD, and the experimental results show the excellence of our model. In addition, there is no publicly available dataset for rubber stamp extraction and removal experiments. To address the scarcity of rubber stamp datasets, we construct a large-scale rubber stamp dataset named LRSD.

Warming had contrasting effects on the importance of facilitative interactions with a cushion nurse species on native and non‐native species in the high‐Andes of central Chile

Alpine habitats are regarded as particularly vulnerable to the effects of climate change. On one hand, global warming is supposed to contributes to alpine environments becoming less stressful. On the other hand, altered snowpack due to warmer temperatures can intensify the stress in these habitats. The presence of non‐native plants on some of these habitats is due to the facilitative effects exerted by native nurse plants, becoming an additional threat. According to the stress gradient hypothesis the importance of facilitative interactions with nurse species is expected to diminish as environmental harshness decreases due to climate change yet remains important if climate change heightens the stress in alpine habitats. However, the responses also depend on climate change's impact on the nurse species. We conducted an experimental warming experiment in the Andes of the central Chile to assess the effects of warmer temperatures on the growth, reproduction and photochemical efficiency of the cushion nurse plant Azorella madreporica. Further we performed a cushion removal experiment involving three native species (Gamocarpha ventosa, Nocaccea magellanica and Rytidosperma pictum) and two non‐native species (Cerastium arvense and Taraxacum officinale) to assess whether facilitative interactions changed with warming. We expected that under warmer conditions facilitation continued be important for the native species but decreased for the non‐natives as the latter are abundant at warmer low elevations. We found that warmer conditions increased the photochemical efficiency and growth of the nurse cushions. Removal of cushions resulted in high mortality rates for all species. However, under warmer conditions, native species exhibited lower survival rates, whereas non‐natives showed no significant changes compared to control groups. In summary, warmer temperatures were beneficial for the nurses maintaining the importance of facilitative interactions for native species, but not for the non‐natives.

Effect of scanning speed on laser cleaning of composite paint layer on aluminum alloy

To explore the effect of varying scanning speeds on laser cleaning of the composite paint layer on the surface of civil aircraft skin, the paint removal transient process by laser ablation was simulated, and laser paint removal experiments of the acrylic polyurethane composite paint layer on the aluminium alloy surface were conducted using nanosecond pulse laser-cleaning equipment at three scanning speeds (v = 900 mm/s, 720 mm/s and 540 mm/s). The experiments show that the topcoat is entirely removed and the primer is partially removed when the scanning speed is 900 mm/s, and the actual paint removal depth is significantly less than the simulation result. The residual primer thickness is further reduced, and the partial oxide film is damaged when the scanning speed is 720 mm/s. The composite paint layer is removed, and part of the aluminium alloy substrate is slightly melted when the scanning speed is 540 mm/s. This study indicates that the ablation behaviour triggers three action mechanisms: plasma shielding, plasma shock-wave and thermal stress paint removal during laser paint removal. With the gradual decrease in scanning speed, the behaviour of ablation paint removal progressively strengthens, the effect of plasma action gradually weakens and the impact of thermal stress remains constant.

Different survival strategies of the phosphate-mineralizing bacterium Enterobacter sp. PMB-5 in response to cadmium stress: Biomineralization, biosorption, and bioaccumulation

The phosphate-mineralizing bacteria (PMBs) has shown great potential as a sustainable solution to support pollution remediation through its induced mineralization capacity. However, few studies have been conducted on the mechanism of cadmium (Cd) tolerance in PMBs. In this study, a PMB strain, Enterobacter sp. PMB-5, screened from Cd-contaminated rhizosphere soil, has high resistance to Cd (540 - 1220 mg/L) and solubilized phosphate (232.08 mg/L). The removal experiments showed that the strain PMB-5 removed 71.69–98.24% and 34.83–76.36% of Cd with and without biomineralization, respectively. The characterization result of SEM, EDS, TEM, XPS and XRD revealed that PMB-5 induced Cd to form amorphous phosphate precipitation through biomineralization and adopted different survival strategies, including biomineralization, bioaccumulation, and biosorption to resistance Cd in the microbial induced phosphate precipitation (MIPP) system and the non-MIPP system, respectively. Moreover, the results of whole genome sequencing and qRT-PCR indicated that phosphorus metabolism genes such as pst, pit, phn, ugp, ppk, etc. and heavy metal tolerance genes (including ion transport, ion efflux, redox, antioxidant stress), such as czcD, zntA, mgtA, mgtC, katE, SOD2, dsbA, cysM, etc. were molecular for the PMB-5 mineralization and Cd tolerance of PMB-5. Together, our findings suggested Enterobacter sp. PMB-5 is a potential target for developing more effective bioinoculants for Cd contamination remediation.

Landscape features, garden management, and microhabitats influence prey removal and predator composition in urban agroecosystems

Agroecosystem management at microhabitat, habitat, and landscape scales shapes natural enemy communities, with critical implications for ecosystem services. Yet few studies examine the impacts of small to large scale habitat management features on predator communities, abundance of predator species, or removal of prey items from urban agroecosystems. In this study, we used observations and a sentinel prey removal experiment to examine the impact of substrate (prey placed on the ground vs. on kale plants), microhabitat (prey placed under vegetation, on bare soil in open areas, or on mulch in open areas), local garden management features, and landscape features on predator species composition and removal of two prey species in urban gardens in the California central coast. We found that both microhabitat characteristics and substrate type shaped prey removal rates within urban gardens, and microhabitat, but not substrate, impacted predator species composition. In addition, both garden management (floral abundance, herbaceous plant richness, and tree and shrub abundance) and landscape features (urban land cover within 2 km) influenced prey removal and predator composition. Nearly all prey removal of eggs was accomplished by ants; larvae predators were more diverse and included ants, birds, lizards, wasps, and spiders. Although predator composition was mediated by many habitat features, prey removal was greater under vegetation, from the ground, when floral abundance in gardens was high, and in gardens with fewer trees and shrubs. Considering how these different management features affect predator foraging behavior and interactions will be a promising next step in this field.

Impacts of multi-pollutants on sulfonamide antibiotic removal from water matrices using layered double hydroxide sorbents

Remediation of sulfamethoxazole (SMX) present in the aqueous environment requires the development of new advanced wastewater treatment technologies, crucial to reduce the toxicity of such pollutants to the environment, supporting urban water reuse. Continuously synthesised layered double hydroxides (LDH) have been applied as a sorbent material for the removal of SMX from water. No equilibrium uptake of SMX was observed from any water matrix. However, an unusual sorption/release behaviour of SMX was observed in the presence of Mg2Al-NO3-LDH, influenced by the characteristics of the water matrix. A maximum SMX removal percentage of 34.7% was reached within 10 min, from ultrapure water, followed by release of SMX back into solution over the following 24 h. Further, Mg2Al-NO3-LDH is shown to release NO3- into all water matrices. It is proposed that NO3- disrupts the SMX-LDH interactions, resulting in release of SMX from the LDH. No initial SMX sorption was observed onto Mg2Al-NO3-LDH when wastewater effluent was the water matrix, likely due to competition for sorption sites on the LDH with multiple pollutants, including metals and additional anionic nutrients, present in the wastewater. This work illustrates the potential for relationships between the sorbent material and water matrix interactions on pollutant sorption behaviour. In addition, the findings highlight the importance of conducting removal experiments at realistic environmental conditions to ensure development of suitable sorbent materials for pollutant remediation.

Impact of remaining roots on soil nematode communities in an aboveground plant functional group removal experiment

Impact of remaining roots on soil nematode communities in an aboveground plant functional group removal experiment

Controlling biases in targeted plant removal experiments.

Targeted removal experiments are a powerful tool to assess the effects of plant species or (functional) groups on ecosystem functions. However, removing plant biomass in itself can bias the observed responses. This bias is commonly addressed by waiting until ecosystem recovery, but this is inherently based on unverified proxies or anecdotal evidence. Statistical control methods are efficient, but restricted in scope by underlying assumptions. We propose accounting for such biases within the experimental design, using a gradient of biomass removal controls. We demonstrate the relevance of this design by presenting (1) conceptual examples of suspected biases and (2) how to observe and control for these biases. Using data from a mycorrhizal association-based removal experiment, we show that ignoring biomass removal biases (including by assuming ecosystem recovery) can lead to incorrect, or even contrary conclusions (e.g. false positive and false negative). Our gradient design can prevent such incorrect interpretations, regardless of whether aboveground biomass has fully recovered. Our approach provides more objective and quantitative insights, independently assessed for each variable, than using a proxy to assume ecosystem recovery. Our approach circumvents the strict statistical assumptions of, for example, ANCOVA and thus offers greater flexibility in data analysis.

A facultative mutualism between habitat-forming species enhances the resistance of rocky shore communities to heat waves

Heat waves have increased in frequency, duration, and magnitude in recent decades, causing mass mortality events in terrestrial and aquatic ecosystems. Arguably, mass mortalities of habitat-forming organisms – i.e., dominant sessile organisms that define habitats via their own physical structure – would be amongst the most dramatic impact of heat waves because of their negative, cascading consequences on their associated biodiversity. However, the resistance of habitat-forming organisms to heat waves can be enhanced if they associate with secondary habitat formers able to tolerate and modulate extreme heat levels. Here we show that a seaweed of the Porphyra/Pyropia (P/P) clade can shield primary habitat-forming mussels, Brachidontes rodriguezii, from the impacts of extreme temperatures in a southwestern Atlantic rocky intertidal shore. By means of P/P removal experiments and surveys, we illustrate that P/P cover (a) buffers temperatures in the understory mussel beds during daytime air exposure periods in the summer, (b) reduces mussel mortality and leads to increased mussel body condition during warm summer periods, and (c) can prevent mass mortality of mussels during the course of a heat wave. Additionally, by means of a mussel removal experiment we illustrate that mussel cover is critical for P/P establishment, which is in consonance with the remarkably higher P/P densities and cover observed in mussel beds relative to exposed rock surfaces across a ~70 km coastal range. Collectively, these findings reveal a facultative mutualism where mussels provide a favorable substrate for P/P colonization and P/P attenuates heat mediated mortality on mussels. The ability of P/P to enhance the resistance of mussel beds to extreme heat events and the occurrence of similar P/P-mussel associations during spring-summer at globally dispersed sites suggests a widespread importance of P/P for the stability of mussel beds and their associated communities under warming climates.

Efficient bisphenol A removal by a photocatalyst-enzyme hybrid system: Horseradish peroxidase integrated with carbon vacancy-modified carbon nitride nanosheets

Peroxidase-based treatment that uses H2O2 as the clean oxidant appears promising for the removal of aqueous phenolic endocrine disrupting chemicals (EDCs). However, oxidative degradation of active heme species at high H2O2 concentrations leads to irreversible enzyme inactivation. The method of combining photocatalysis and enzyme biocatalysis could alleviate the issue by photocatalytic in-situ H2O2 production. In this study, we constructed a photocatalyst-enzyme hybrid system that integrated the horseradish peroxidase with carbon vacancy-modified carbon nitride nanosheets (HRP@ACNNs). Attributed to the modified carbon nitride, the HRP@ACNNs exhibited higher substrate affinity and comparable catalytic efficiency compared to free HRP. This photocatalyst-enzyme hybrid system could offer H2O2 continuously to sustain enzymatic catalysis without enzyme inactivation as well as stabilize the enzyme. The bisphenol A (BPA) removal experiments further confirmed the effectiveness in treating phenolic EDCs of the prepared HRP@ACNNs.

Photocatalytic NOx removal with TiO2-impregnated 3D-printed PET supports

In this work, we investigated the photocatalytic removal of NOx using 3D-printed supports. Monolithic supports with internal channels were fabricated by Fused Modelling Deposition (FDM) using PET as the filament feedstock. The printing parameters of the supports were optimized to maximize the exposure of the photocatalyst to UV light throughout the monolithic PET printed supports. The removal experiments were carried out in a continuous gas phase flow reactor, which was custom designed in-house incorporating a 3D printed PET support impregnated with TiO2 as photocatalyst. The impregnated and non-impregnated supports were characterized by diffuse reflectance spectrometry, SEM and AFM. The effect of several key-factors on the NOx removal capacity was investigated, including the type of PET filament (native recycled, BPET vs. glycol-modified, PETG), the type of TiO2 (P25 vs. Hombikat UV-100), the UV light source (LED vs. tubular lamps), and the number of deposited TiO2 layers. The highest NO and NOx removal were achieved by using PETG supports coated with a single layer of Hombikat UV-100 and irradiating the flat reactor from both sides using two sets of black light lamps. However, the highest selectivity toward nitrate formation was obtained when using P25 under the same experimental conditions. This work demonstrates that 3D printing is a reliable and powerful technique for fabricating photocatalytic reactive supports that can serve as a versatile platform for evaluating photocatalytic performance.