Heterogeneous Fenton Process Research Articles

Fe-containing carbon-coated monoliths prepared by CVD in gaseous toluene abatement - parametric analysis of the Fenton process

The degradation of toluene (present in a gas stream) by the heterogeneous Fenton process was evaluated in a bubble column reactor. The process was catalyzed by macrostructured carbon-coated monoliths that were synthesized by chemical vapor deposition (CVD), which allowed carbon growth in honeycomb cordierite monoliths, while the iron (metal phase) was incorporated by adsorption. A detailed parametric study was carried out to evaluate the effect of the main variables and process operating conditions, namely channel density of the monolith, hydrogen peroxide concentration, pH and catalyst load; as process responses, the amount of toluene transferred - η, hydrogen peroxide consumption and dissolved organic carbon (DOC) concentration in the liquid phase were assessed. The maximum ratio between the toluene transferred per catalysts mass - η/W - (6.8 ×10−2 moltoluene gcat−1), with total oxidant consumption and higher intermediate compounds remaining in solution (DOC = 33 mgC dm−3), was reached when the process was performed with a monolith with a channel density of 230 cpsi, initial pH = 3.0, [catalyst] = 0.8 g dm−3, [H2O2] = 20 mmol dm−3. During all experiments, only a small amount of iron was leached from the catalyst to the liquid phase (ca. ≤1.0 wt%), proving its stability for such application; in fact, it was found that homogenous process contribution due to iron leaching towards the overall performance is ca. 10%.

Catalytic adsorptive elimination of deleterious contaminant in a pilot fluidised-bed reactor by granulated Fe3O4/Cu-MOF/cellulose nanocomposites: RSM optimisation and CFD approach

ABSTRACT A novel catalyst was synthesised in a way that it could be applied in simultaneous adsorption and heterogeneous Fenton processes. The granulated Fe3O4/CuBDC/Cellulose nanocomposites were synthesised with a novel in-situ granulation method in a rotary autoclave reactor, and they were efficient in the removal of a detrimental trisazo dye, direct blue 71 (DB71). The catalysts were characterised by various analyses. In order to fulfill the expectation from the catalysts traits, many parameters were evaluated meticulously such as the effect of modification of Fe3O4 nanoparticles, the ratio of Fe3O4 to CuBDC in the nanocomposite, the stability of the catalyst, and diverse catalyst characterisations (SEM, EDX, FTIR, XRD, BET, XPS). The rotating speed of the autoclave was optimised by carrying out computational fluid dynamics (CFD) simulations; 60 rpm rotating speed was selected among the other ones to achieve catalysts that were more homogeneous. Moreover, the dye elimination process was conducted in a pilot fluidised bed reactor. The impacts of three diverse parameters on the removal efficiency were assessed by response surface method (RSM) to optimise them, 96.85% dye removal was achieved in a 30-min process (the initial DB71 concentration = 10 mg/L, the H2O2 concentration = 8.55 mM, and the catalyst dosage = 7.12 g/L). The study of the dye elimination mechanism and thermodynamics of the process indicated endothermic, spontaneous, favourable, and physical adsorption of DB71 on the catalysts. Reutilisation of granulated catalysts at least for ten treatment cycles without regeneration process incorporating high and stable degradation efficiency (11% performance reduction), exhibited the exceeding performance of the highly durable well-designed catalysts in the simultaneous adsorption and heterogeneous Fenton processes.

The Role of 3D Printing in the Development of a Catalytic System for the Heterogeneous Fenton Process.

Recycling of catalysts is often performed. Additive manufacturing (AM) received increasing attention in recent years in various fields such as engineering and medicine, among others. More recently, the fabrication of three-dimensional objects used as scaffolds in heterogeneous catalysis has shown innumerable advantages, such as easier handling and waste reduction, both leading to a reduction in times and costs. In this work, the fabrication and use of 3D-printed recyclable polylactic acid (PLA) scaffolds coated with an iron oxide active catalyst for Fenton reactions applied to aromatic model molecules, is presented. These molecules are representative of a wider class of intractable organic compounds, often present in industrial wastewater. The 3D-printed PLA-coated scaffolds were also tested using an industrial wastewater, determining the chemical oxygen demand (COD). The catalyst is characterized using electron microscopy coupled to elemental analysis (SEM/EDX) and thermogravimetry, demonstrating that coating leach is very limited, and it can be easily recovered and reused many times.

Rapid Degradation of Methyl Orange by Heterogeneous Fenton Process Using Fewo4 Nanocatalyst Prepared by Wet Chemical Route.

To remove the hazardous organic adulterants from the wastewater, iron tungstate nanoparticles were prepared by a simple wet chemical route. These nanoparticles characterized to be polydispersed, polycrystalline with irregular spherical morphologies without any notable impurities were used as a catalyst for heterogeneous Fenton reaction, an advanced oxidation process. Their catalytic properties, degradation efficiency, and recyclability were analyzed for methyl orange degradation, a common -reactive azo dye in an acidic aqueous. The rapid fall of absorption peak exhibits the complete degradation of dye within 50 minutes of reaction with discoloration efficiency of ~97% without any additional external exposures such as light or ultrasonic waves. In addition to this, the durability of the FeWO4 nanoparticles catalyst is proved to be maintained over five catalyst reuse cycles, which strongly suggests that at this present scenario of ecological deterioration, the chosen nanomaterial is one of the apt candidates for azo dye removal by heterogeneous dark Fenton process.

Synergistic effect of Fenton oxidation and adsorption process in treatment of azo printing dye: DSD optimization and reaction mechanism interpretation

ABSTRACT The main challenges to overcome within the Fenton process are the acidic pH as an optimal reaction condition, sludge formation in neutral pH medium and high toxicity of treated printing wastewater due to the generation of contaminating by-products. This research discusses the catalytic activity of homogeneous (FeSO4/H2O2) and heterogeneous (Fe2(MoO4)3/H2O2) Fenton processes in treatment of Yellow azo printing dye in synthetic aqueous solution and real printing effluent, with an integration of adsorption on functionalized biochar synthesized from wild plum kernels. The definitive screening design (DSD), was used to design the experiment. Independent variables were initial dye concentration (20–180 mg L−1), iron concentration (0.75–60 mg L−1), pH (2–10) and hydrogen peroxide concentration (1–11 mM). Higher decolourization efficiency of 79% was obtained within homogeneous Fenton treatment of printing wastewater, in comparison to heterogeneous Fenton treatment (54%), after a reaction time of 60 min. Same trend of mineralization degree was established: COD removal was 59% and 33% for homogeneous and heterogeneous Fenton process, respectively. The application of adsorption treatment has achieved significant advantages in terms of toxicity reduction (95%) and decolourization efficiency (90% of TOC removal and 22% of dye removal) of treated samples, even at neutral pH medium. Degradation mechanisms within Fenton and adsorption processes were proposed based on the qualitative gas chromatography/mass spectrometry analysis, physico-chemical properties of dye degradation products and functionalized biochar. Overall, the homogeneous Fenton/adsorption combined process can be potentially used as a treatment to remove azo dyes from contaminated water.

Degradation of Methylene Blue Using Fly Ash as a Heterogeneous Fenton Catalyst

Fly ash was used as a heterogeneous Fenton catalyst to degrade methylene blue in aqueous solution. The influence off key operating parameters on the degradation efficiency, including the concentrations of hydrogen peroxide and methylene blue, catalyst dosage, and the initial pH, were studied. The optimal degradation conditions were 2 mmol/L hydrogen peroxide, 4 mg/mL of fly ash, and pH 3. Under these conditions, the degradation efficiency was approximately 93% within 4 h. The degradation of methylene blue by heterogenous Fenton process followed the pseudo-first order kinetics and the activation energy shows that the reaction is thermodynamically feasible. Fly ash demonstrated acceptable reusability after 3 successive cycles. The results in the present study indicated that fly ash is a potent cost-effective catalyst for the degradation of organic dyes in aqueous solution by a heterogeneous Fenton process.

Application and mechanism of Fenton-like iron-based functional materials for arsenite removal

Between the two major arsenic-containing salts in natural water, arsenite (As(III)) is far more harmful to human and the environment than arsenate (As(V)) due to its high toxicity and transportability. Therefore, preoxidation of As(III) to As(V) is considered to be an effective means to reduce the toxicity of arsenic and to promote the removal efficiency of arsenic. Due to their high catalytic activity and arsenic affinity, iron-based functional materials can quickly oxidize As(III) to As(V) in heterogeneous Fenton-like systems, and then remove As(V) from water through adsorption and surface coprecipitation. In this review, the effects of different iron-based functional materials such as zero-valent iron and iron (hydroxy) oxides on arsenic removal are compared, and the catalytic oxidation mechanism of As(III) in heterogeneous Fenton process is further clarified. Finally, the main challenges and opportunities faced by iron-based As(III) oxidation functional materials are prospected.

Bifunctional Mo-doped FeCo–Se aerogels catalysts with excellent OER and ORR activities for electro-Fenton process

Antibiotic pollution in aqueous solutions seriously endangers the natural environment and public health. In this work, Mo-doped transition metal FeCo–Se metal aerogels (MAs) were investigated as bifunctional catalysts for the removal of sulfamethazine (SMT) in solution. The optimal Mo0.3Fe1Co3–Se catalyst can remove 97.7% of SMT within 60 min (SMT content: 10 mg/L, current intensity: 10 mA/cm2). The unique porous cross-linked structure of aerogel confered the catalyst sufficient active sites and efficient mass transfer channels. For the anode, Mo0.3Fe1Co3–Se MAs exhibits superior oxygen evolution reaction (OER) property, with an overpotential of only 235 mV (10 mA/cm2). Compared with Fe1Co3 MAs or Mo0.3Fe1Co3 MAs, density functional theory (DFT) demonstrated that the better catalytic capacity of Mo0.3Fe1Co3–Se MAs is attributed to the doping of Mo species and selenization lowers the energy barrier for the ∗OOH to O2 step in the OER process. Excellent OER performance ensures the self-oxygenation in this system, avoiding the addition of air or oxygen in the traditional electro-Fenton process. For the cathode, Mo doping can lead to the lattice contraction and metallic character of CoSe2, which is beneficial to accelerate electron transfer. The adjacent Co active sites effectively adsorb ∗OOH and inhibit the breakage of the O–O bond. Rotating ring disk electrode (RRDE) test indicated that Mo0.3Fe1Co3–Se MAs has an excellent 2e− ORR activity with H2O2 selectivity up to 88%, and the generated H2O2 is activated by the adjacent Fe site through heterogeneous Fenton process to generate ·OH.

Chitosan Fibers Loaded with Limonite as a Catalyst for the Decolorization of Methylene Blue via a Persulfate-Based Advanced Oxidation Process.

Wastewater generated from industries seriously impacts the environment. Conventional biological and physiochemical treatment methods for wastewater containing organic molecules have some limitations. Therefore, identifying other alternative methods or processes that are more suitable to degrade organic molecules and lower chemical oxygen demand (COD) in wastewater is necessary. Heterogeneous Fenton processes and persulfate (PS) oxidation are advanced oxidation processes (AOPs) that degrade organic pollutants via reactive radical species. Therefore, in this study, limonite powder was incorporated into porous regenerated chitosan fibers and further used as a heterogeneous catalyst to decompose methylene blue (MB) via sulfate radical-based AOPs. Limonite was used as a heterogeneous catalyst in this process to generate the persulfate radicals (SO4-·) that initiate the decolorization process. Limonite-chitosan fibers were produced to effectively recover the limonite powder so that the catalyst can be reused repeatedly. The formation of limonite-chitosan fibers viewed under a field emission scanning electron microscope (FESEM) showed that the limonite powder was well distributed in both the surface and cross-section area. The effectiveness of limonite-chitosan fibers as a catalyst under PS activation achieved an MB decolorization of 78% after 14 min. The stability and reusability of chitosan-limonite fibers were evaluated and measured in cycles 1 to 10 under optimal conditions. After 10 cycles of repeated use, the limonite-chitosan fiber maintained its performance up to 86%, revealing that limonite-containing chitosan fibers are a promising reusable catalyst material.

Pre-treatment of real pharmaceutical wastewater by heterogeneous Fenton and persulfate oxidation processes

This study compares the pre-oxidation of pharmaceutical wastewater by hydroxyl radical based advanced oxidation (HR-AOP) and a sulfate radical based advanced oxidation process (SR-AOP). The heterogeneous Fenton process is chosen as a model HR-AOP and persulfate (PS) activation as a model SR-AOP. The pre-treatment efficacy of both processes in terms of TOC, and COD removals using Fe3O4-rGO catalyst were considered. Under the investigated experimental conditions, both processes yielded fluctuating COD values with time. The heterogeneous Fenton process discovered to be the most efficient to remove 68.7% TOC in 180 min of treatment, when Fe3O4-rGO: H2O2 = 300 mg L−1:150 mM H2O2 was used at pH 3. Notably, the heterogeneous Fenton system was not considerably inhibited at the natural pH of pharmaceutical wastewater (6.75), as the process successfully removed 64.6% TOC. On the other hand, in persulfate activation studies, Fe3O4-rGO: PS = 400 mg L−1: 5 mM was the ideal condition for removing 59.5% TOC in 180 min at pH 3. Whereas the natural pH condition significantly inhibited the TOC removal, as only 20.8% TOC removal was feasible. The wastewater characterisation before and after Fenton treatment reveals that Fenton oxidation leads to an increase in inorganics (chlorides: 160 ± 15 mg L−1, nitrates: 63.14 ± 3.08 mg L−1, sulfates: 266.31 ± 31.39 mg L−1) necessitating an additional treatment step to reduce COD and inorganics further.

Application of Fe and Cu nanoparticles for methyl orange removal from water and water-ethanol mixtures under various experimental conditions

In this study, metallic iron nanoparticles (Fe NPs) and metallic copper nanoparticles (Cu NPs) were prepared, characterized, and used in the removal of methyl orange (MO) dye. The experiments investigated first the UV–Vis spectra of dye molecules in three types of solvents (water, water-ethanol, and water-dimethyl sulfoxide). The removal of MO was then conducted under various experimental conditions to investigate the effects of solvent type, nanoparticles dosage, salinity of the solutions, temperature, and shaking time. The highest extent of MO removal was achieved in water solutions. Under all experimental conditions, Fe NPs showed higher efficiency than Cu NPs in MO removal. Moreover, heterogeneous Fenton process led to smaller MO removal when compared with the direct use of the nanoparticles, for both water and water-ethanol solutions. From a kinetic perspective, the dye removal process was much faster in water than in water-ethanol mixtures, and the data followed pseudo-second order rate equation.

A general and programmable preparation of α-MnO2/GO/CS aerogels used for efficient degradation of MB in wastewater

Heterogeneous Fenton reaction, as an efficient advanced oxidation process (AOP), has been proved as a promising method to treat organic wastewater. In this study, combining the outstanding adsorption capacity of aerogels and the excellent catalytic ability of α-MnO2, various composite aerogels functionalized by α-MnO2 through double cross-linking structures were developed to degrade methylene blue (MB) in a heterogeneous Fenton process. Herein, a series of α-MnO2/GO/CS composite aerogels with different amount of graphene oxide (GO) were prepared, and detailed characterizations were made to evaluate the structures of aerogels. Finally, aerogel-5 with the most amount of GO was proved to be the optimal catalyst, which could degrade 99.7 % MB in 50 min under an optimal condition (50 mL 30 mg/L MB, 0.05 g aerogels, 2 mL 30 % H2O2, pH = 10). Especially, aerogel-5 also displayed excellent degradation efficiency (D%) when used in higher concentration MB solution in 15 min (98.4 % for 100 mg/L MB, 98.1 % for 150 mg/L MB, 97.4 % for 200 mg/L MB). In addition, the D% still reached 92.7 % after the 5th reuse. Therefore, this work developed a high active composite catalyst, which would be promising for highly efficient treatment of dye wastewater.

Gaseous toluene abatement by the heterogeneous Fenton-like process using iron/carbon-coated monolith as catalyst: Proof of concept

The degradation of toluene from a gas stream by the heterogeneous Fenton process was evaluated over a carbon-coated monolith impregnated or not with iron as catalyst in a bubble column reactor (BCR). The carbon-coated monolith support (CM) was prepared by chemical vapor deposition and the catalyst (CM impregnated with iron – herein called CM-Fe) by adsorption. In the screening of processes (absorption, adsorption and reaction), it was shown that the heterogeneous Fenton process catalyzed by CM-Fe presents the best efficiency (toluene transfer (η) = 10 × 10−3 mol, for 300 mL of liquid solution and 0.69 g of catalyst). Finally, the stability of CM and CM-Fe was evaluated, wherein ten consecutive runs were carried out, the results showing a considerable deactivation of CM during the first five cycles. In contrast, the CM-Fe sample only slightly decreases its activity from the 1st to 2nd cycle (due to a small amount of iron leached from the monolith, 0.7%), remaining stable after that, which is important for applying this technology at the industrial level. This work showed for the first time that the treatment of gaseous effluents containing organic compounds by the Fenton process (which takes place in the liquid phase) using a carbon-coated monolith impregnated with iron is plausible, so the proof of concept was successfully accomplished.

Valorisation of residual iron dust as Fenton catalyst for pulp and paper wastewater treatment

In this work, the performance of residual iron dust (RID) from metallurgic industry was assessed as Fenton catalyst for the treatment of real pulp bleaching wastewater. The focus was on the removal of recalcitrant pollutants AOX (adsorbable organic halides), by a novel, cleaner, and cost-effective circular solution based on a waste-derived catalyst. The behaviour of RID as iron source was firstly assessed by performing leaching tests at different RID:wastewater w/v ratios and contact time. Afterwards, RID-catalysed homogeneous and heterogeneous Fenton processes were conducted to maximise AOX removal from the pulp bleaching wastewater. Reusability of RID was assessed by a simple collect-and-reuse methodology, without any modification.Similar AOX removal under less consumption of chemicals was achieved with the novel heterogeneous Fenton process. Reaction in the bulk solution was the main pathway of AOX removal, given that the low surface area and porosity of the material did not allow for a high contribution of surface reaction to the overall performance. Moreover, AOX removal was similar over two consecutive treatment cycles, with Fenton process being responsible for 56.7–62.1% removal of AOX from the wastewater, and the leaching step adding 11.4–13.2%. At the end of treatment, COD either decreased (1st cycle) or remained unchanged (2nd and 3rd cycle). The operating cost of the optimised heterogeneous Fenton was 3–11% lower than under conventional Fenton process. This work presented a novel, circular solution based on a low-cost waste-derived catalyst, advancing the knowledge needed to foster industrial application of such technologies to increase industrial environmental performance and efficiency.

Degradation of Brilliant Blue by Heterogeneous Fenton and UV-Fenton Processes

Degradation of Brilliant Blue by Heterogeneous Fenton and UV-Fenton Processes

Flocculation synergistic with nano zero-valent iron augmented attapulgite @ chitosan as Fenton-like catalyst for the treatment of landfill leachate

ABSTRACT In this study, nano-zero-valent iron (NZVI) was added to attapulgite/chitosan and used as a catalyst in the heterogeneous Fenton process to degrade stabilized landfill leachate. Landfill leachate has serious environmental impacts due to the complexity and diversity of its pollutants. A magnetic catalyst (NZVI@PATP/CS) was prepared by a liquid-phase reduction method. The NZVI@PATP/CS were characterized by XRD, FTIR and SEM. The pH of leachate and the dosage of catalyst and H2O2 were changed to determine the best-operating conditions for the effective removal of chemical oxygen demand (COD) and total phosphorus(TP). To understand the adsorption degradation mechanism, the quenching experiments of free radicals were carried out. The results showed that the degradation rates of COD and TP were 66% and 92%, respectively, under the optimum pH value of 8, the dosage of H2O2 of 5 mL, and the dosage of the catalyst of 0.25 g for 60 min.

Enhanced reactivity of the CuO-Fe2O3 intimate heterojunction for the oxidation of quinoline yellow dye (E104).

This research work describes the degradation of quinoline yellow (QY) in aqueous solutions by the heterogeneous Fenton and photo-Fenton processes in the presence of CuO/Fe2O3 photocatalyst. CuO/Fe2O3 derived from LDH structure was synthesized by the co-precipitation method. The physiochemical characteristics of CuO/Fe2O3 were described by XRD, TEM/SEM, BET surface area, and FTIR techniques. The effects of pH, H2O2concentration, dye concentration, catalyst dose, reaction temperature, and reusability of catalyst on the QY decolorization efficiency were studied. The results indicated that a complete removal of QY was achieved within 150 min, when the H2O2 and QY concentrations were 27.6 mM and 100 mg/L, respectively. The rate constants for QY removal by the heterogeneous Fenton system were calculated, and the experimental data were found to fit the pseudo-first order model. Under optimal conditions, the rate constants were, respectively, 0.02032 and 0.01715 min-1 for the photo-Fenton and Fenton systems; this means that the addition of light has not a noticeable effect.

Nano valent zero iron (NZVI) immobilized CNTs hollow fiber membrane for flow-through heterogeneous Fenton process

Fenton, a conventional technology, has been widely employed for wastewater purification, but it still suffers from the unsatisfactory capability for pollutants degradation. Herein, a membrane-based Fenton process was proposed by immobilizing nano zero valent iron (NZVI) in a CNT membrane (Fe0-CNT catalytic membrane) for accelerating pollutants degradation efficiency. It realizes a promotion on·OH generation rate from H2O2 catalyzed by NZVI catalyst owing to the cycle of between ferrous and ferric ions during the Fenton process. Meanwhile, mass transfer improvement can be achieved due to the liquid convection in the membrane pore via the flow-through process. As a result, the Fe0-CNT catalytic membrane presented a high removal efficiency of 98% for bisphenol A (BPA) under an optimum operation condition. Also, the prepared Fe0-CNT catalytic membrane showed excellent degradation efficiency for other organic contaminants, such as phenol (80.6%), sulfamethoxazole (SMX, 95.5%) and paracetamol (ACM, 84.1%). Furthermore, the environmental factors (various of anion ions, such as Cl-, HCO3- and NO3- and natural organic matter) presented negligible influences on organic pollutants degradation via Fe0-CNT catalytic membrane, suggesting a good potential for factual wastewater treatment application. Based on the results, this work introduces a novel insight into the design of highly efficient Fenton process using membrane-based catalyst for pollution abatement.

Ectomycorrhizal Fungal Transformation of Dissolved Organic Matter: Consequences for Reductive Iron Oxide Dissolution and Fenton-Based Oxidation of Mineral-Associated Organic Matter

Recent studies have shown that dissolved organic matter (DOM) decomposed by ectomycorrhizal (ECM) fungi increases adsorptive properties of organic matter towards soil mineral surfaces. Concomitantly, ECM fungi secrete secondary metabolites with iron reducing capacity that are thought to participate in non-enzymatic Fenton-based decomposition of DOM. The aim of this study was to investigate if the iron reduction induced by the ECM fungus Paxillus involutus during organic matter decomposition was conserved in the decomposed DOM. We explored how the modified DOM reductively dissolved ferrihydrite and goethite nanoparticles and how these processes affected the reactions with H2O2 and the Fenton-based oxidation of mineral-associated organic matter. Culture filtrates were obtained from incubation of the ECM fungus on DOM from forest litter of a spruce forest. This modified DOM was separated by extraction into an ethyl acetate and a water fraction. These fractions were reacted with ferrihydrite and goethite in absence and presence of H2O2. Dissolved Fe2+ and HO• were measured and the reactions at the iron oxide-water interfaces were monitored in real-time with in-situ IR spectroscopy. Experiments showed that decomposition of DOM by P. involutus generated a modified DOM that displayed an increased and persistent reductive capacity. Most of the reductants were isolated in the aromatic- and carboxyl-dominated ethyl acetate fraction but some reduction capacity was also captured in the water fraction mainly containing carbohydrates. Reductive dissolution was more extensive for ferrihydrite than goethite, and this process generated significant oxidation of the DOM-ferrihydrite associations. Oxidation of adsorbed DOM was triggered by H2O2via heterogenous and homogeneous Fenton reactions. These oxidation processes were favored by ferrihydrite because of a high reduction potential and a high efficiency of heterogeneous Fenton as compared to goethite. An optimal timing between the heterogeneous and homogeneous Fenton processes triggered extensive radical oxidation of the DOM-ferrihydrite associations generating a high concentration of surface-associated oxalate. Overall, the results show that organic matter associated with ferrihydrite may be more susceptible to radical oxidation than on goethite, and that fungal decomposition of DOM in general may have consequences for other important soil processes such as mineral dissolution, adsorption and initiation of radical reactions.

Heterogeneous Advanced Oxidation Processes: Current Approaches for Wastewater Treatment

Nowadays, water pollution is one of the most dangerous environmental problems in the world. The presence of the so-called emerging pollutants in the different water bodies, impossible to eliminate through conventional biological and physical treatments used in wastewater treatment plants due to their persistent and recalcitrant nature, means that pollution continues growing throughout the world. The presence of these emerging pollutants involves serious risks to human and animal health for aquatic and terrestrial organisms. Therefore, in recent years, advanced oxidation processes (AOPs) have been postulated as a viable, innovative and efficient technology for the elimination of these types of compounds from water bodies. The oxidation/reduction reactions triggered in most of these processes require a suitable catalyst. The most recent research focuses on the use and development of different types of heterogeneous catalysts, which are capable of overcoming some of the operational limitations of homogeneous processes such as the generation of metallic sludge, difficult separation of treated water and narrow working pH. This review details the current advances in the field of heterogeneous AOPs, Fenton processes and photocatalysts for the removal of different types of emerging pollutants.