Mineralization Of Organic Pollutants Research Articles

Effective mineralization of organic pollutants in real shale gas flowback water via Fenton reactions over CuNiAl LDHs catalysts

Effective mineralization of organic pollutants in real shale gas flowback water via Fenton reactions over CuNiAl LDHs catalysts

In Situ and Ex Situ Bioremediation of Different Persistent Soil Pollutants as Agroecology Tool

Contamination or pollution of our environment has become a real global concern, especially in parallel with the increasing evolution of urbanization and industrialization, which in turn have released a plethora of different pollutants that end up being deposited in soils. It is crucial to investigate solutions that can minimize the extent of damage, and that are cost-effective, feasible and environmentally friendly, to treat a wide variety of contaminants in soils, as well as to detoxify various compounds. Bioremediation is a safe technique that has demonstrated satisfactory results and is easy to apply and maintain. This technique explores the degradation pathways of various biological agents (microorganisms, plants, algae, etc.) to neutralize contaminants. It is based on biodegradation through a complete mineralization of organic pollutants into inorganic innocuous compounds, such as carbon dioxide and water. This review aims to determine the feasibility of bioremediation as a cleanup technology for soils contaminated with pesticides, agrochemicals, chlorinated compounds, heavy metals, organic halogens, greenhouse gases, petroleum hydrocarbons, and many others, either in situ or ex situ. Different bioremediation approaches are described and compared, showing their advantages and drawbacks from a critical point of view. Moreover, both the economic and technical barriers of bioremediation are addressed, along with the outlook for the role of microorganisms in the process, the aim to identify future directions, and the application feasibility of this process.

In-situ Fe–O co-doped carbon nitride heterogenous catalyst for enhanced photo-Fenton oxidation performance towards recalcitrant organic pollutants

One-step and in-situ FeCl3-participated molten urea thermal polymerization strategy is designed to prepare Fe–O co-doped carbon nitride photo-Fenton catalyst (Fe/OCN). Fe/OCN exhibits remarkable photo-Fenton catalytic oxidation capacity towards recalcitrant organic pollutants, in which 0.31 wt% Fe/OCN with optimal Fe-doping level exhibits significantly 60 and 6.3 times higher pseudo-first-order kinetic constant than single photocatalysis and Fenton system in the degradation of methyl orange. The enhancement of photo-Fenton catalytic performance is mainly ascribed to the realization of ideal Fe–O and Fe–N coordination structure in the framework of polymeric carbon nitride, which can not only serve as prime sites for the adsorption of target pollutants molecules and transfer channels for directed migration of photogenerated charges, but also well-modulate electronic structure and band structure of Fe/OCN. Accordingly, the resulting boosted charge carriers separation and transfer dynamics and increased electron density around Fe active centers facilitate ≡Fe(II) regeneration and H2O2 activation, leading to the significant production of plentiful reactive species responsible for degradation and mineralization of organic pollutants. The present work provides new insight into the optimized design and precise regulation of carbon nitride-based photo-Fenton system for advanced wastewater treatment.

A double transition metal MXene/S-scheme heterojunction composite with improved photoelectrochemical and photocatalytic properties

Herein, a novel double transition metal MXene (DTMXene) S-scheme photocatalyst was constructed with potential application in mineralization of organic pollutants found in water. The fabrication of the DTMXene heterojunction photocatalyst (Ce2S3/WO3@TiVCTx) was achieved through an ultrasonication and calcination approach. The highly conductive DTMXene (TiVC), was incorporated into an S-scheme heterojunction to maximize the separation of the charge kinetics, subsequently enhancing the photocatalytic properties. The phase structure, morphology, photoelectrochemical, and optical properties of the synthesized materials were characterized and confirmed by spectroscopic, microscopic, and photoelectrochemical techniques. The DTMXene-based heterojunction photocatalyst showed a significant increase in optical and electrochemical properties compared to the pristine materials of the 7 wt%-Ce2S3/WO3@TiVC-7 wt% ternary composite exhibiting excellent photoelectrochemical properties, including a weak PL emission intensity and a decreased EIS resistance, indicating efficient separation and transfer of photogenerated charge carriers. A significant improvement of the photocatalytic and electrochemical properties is attributed to the excellent conductive nature of the DTMXene, which facilitates the separation of the photogenerated charge carriers. This work therefore gives a novel approach to the fabrication of a reliable DTMXene-based photocatalyst with enhanced potential in environmental remediation, hydrogen evolution, and energy storage.

Enhanced Mineralization of Organic Pollutants through Atomic Hydrogen-Mediated Alternative Transformation Pathways.

Electrocatalytic hydrogen atom-hydroxyl radical (H*-·OH) redox system is a promising approach for contaminant removal and mineralization. However, its working mechanism, especially the effect of H*, remains unclear, hindering its practical application. Herein, we constructed an electrochemical reactor equipped with our self-made Pd-loaded Ti/TiO2 nanotube cathode and a commercial boron-doped diamond anode. After fulfilling the electrode characterization and free radical detection, we employed coumarin and 7-azido-4-methylcoumarin as probes to confirm the participation of H* in the transformation of organic compounds. A comprehensive study on the degradation kinetics, reaction, and mineralization mechanisms using benzoic acid (BA) and 4-chlorophenol (4-CP) as model compounds was further conducted. The rate constants and total organic carbon removal of BA and 4-CP in the redox system increased compared with those of the individual oxidation and reduction processes. Theoretical calculations demonstrate that H* opens up alternative pathways for BA and 4-CP ring cleavage, forming quinones as reactive intermediates. Furthermore, H* facilitates the mineralization of the typical intermediates, maleic acid and fumaric acid, through C=C bond addition and H-abstraction from the 1,1-diol structure. The presence of H* provides alternative pathways for pollutant transformation, consequently reducing the treatment duration.

An Overview of the Degradation and Removal of Pesticide Residues from Water and Agricultural Runoff using Nanoparticles and Nanocomposites

: A high percentage of the applied chemicals on farmlands find their way into the water bodies and groundwater through agricultural runoff and leaching/percolation. Therefore, multiple remediation techniques need to be employed to deter the menace of pesticide residue contamination. Therefore, this review aimed to compute the most suitable degradation conditions for the removal of pesticide residue from water and agricultural runoff using nanomaterials. The review touches on the aspect of adsorption and photocatalytic degradation methods using nanomaterials and the most prominent factors that affect the degradation process. Information from recently published articles, book chapters, and conference proceedings were carefully studied and analyzed. It was revealed that heterogeneous photocatalysis shows the capability of complete mineralization of organic pollutants under optimum experimental conditions. Moreover, it is crucial to consider experimental conditions that could be applicable in the field to achieve a better result. It has been observed that integrating nanoremediation with other degradation methods to create a hybrid technique may play a crucial role in removing pesticide residues from agricultural runoff. However, the detrimental effects of the nanomaterials if any on the environmental matrices need to be taken under consideration to avoid the menace similar to plastic pollution as a result of extensive production and application of nanomaterials.

N-coordinated single cobalt atoms catalyst triggering concerted radical-nonradical process in catalytic ozonation for efficient water decontamination

Heterogeneous catalytic ozonation (HCO) has been developed as a promising technology for wastewater treatment, while traditional radical-based HCO process still suffers from insufficient mineralization of organic pollutants. Herein, we constructed a N-coordinated single cobalt atoms catalyst (CoSAC-N-C) triggering concerted radical-nonradical process in catalytic ozonation for efficient decontamination of pollutants. Experiments and theoretical calculations proved that mediate O in O3 obtained electrons from electron-rich N sites for hydroxyl radical (·OH) production, and the terminal O in O3 was attracted on electron-deficient Co sites for nonradical *O generation by O-O cleavage. The synergistic oxidation of ·OH and *O enabled excellent pollutants mineralization, surpassing most of conventional HCO catalysts. CoSAC-N-C exhibited excellent treatment performance for the coking wastewater in a continuous-flow reactor with COD reducing from 86 mg/L to less than 50 mg/L. This work provided a viable strategy of developing dual-site HCO catalysts to promote concerted radical-nonradical oxidations for wastewater treatment.

Heterogeneous CuS QDs/BiVO4@Y2O2S Nanoreactor for Monitorable Photocatalysis.

Exploration of multifunctional integrated catalysts is of great significance for photocatalysis toward practical application. Herein, a 1D confined nanoreactor with a heterogeneous core-shell structure is designed for synergies of efficient catalysis and temperature monitoring by custom encapsulation of Z-scheme heterojunction CuS quantum dots/BiVO4 (CuS QDs/BiVO4) and Y2O2S-Er, Yb. The dispersed active sites created by the QDs with high surface energy improve the mass transfer efficiency, and the efficient electron transport channels at the heterogeneous interface extend the carrier lifetime, which endows the nanoreactor with excellent catalytic performance. Meanwhile, real-time temperature monitoring is realized based on the thermally coupled levels 2H11/2/4S3/2→4I15/2 of Er3+ using fluorescence intensity ratio, which enables the monitorable photocatalysis. Furthermore, the nanoreactor with a multidimensional structure increases effective intermolecular collisions to facilitate the catalytic process by restricting the reaction within distinct enclosed spaces and circumvents potential unknown interaction effects. The design of multi-space nanoconfined reactors opens up a new avenue to modulate catalyst function, providing a unique perspective for photocatalytic applications in the mineralization of organic pollutants, hydrogen production, and nitrogen fixation.

Cyanide-Isolated Cobalt Catalyst for Ultraefficient Advanced Oxidation Treatment.

Catalyst design with a "Co-N-C" structure at the atomic level has shown great interest for peroxymonosulfate (PMS) activation toward advanced oxidation water treatment. Here, we present an innovative way of producing cobalt hexacyanocobaltate (Co-HCC) with an abundance of atomically isolated CoII-NC sites at the outer surface. This material allows ultraefficient PMS activation to generate plenty of sulfate and hydroxyl radicals, with a turnover frequency much higher than those of most cobalt-based catalysts reported so far and even the homogeneous catalysis by Co2+ ions. We gained fundamental insights on its unprecedently high catalytic performance based on experimental results and computational study. Then, we controlled the growth of Co-HCC on a ceramic membrane to form a confined oxidation environment that utilizes the extended surface area and maximal exposure of short-lived radicals for a fast removal of organic pollutants that enter the pores. As a result, this catalytic membrane achieves complete disruption of micropollutants under a water flux up to 10,000 LMH (merely 0.2 s retention time) and further >90% mineralization of organic pollutants in complex industrial wastewater matrices (<100 s retention time), together with the merits of operational simplicity and great longevity (2 weeks continuous run). Our study elicits a new milestone in "Co-N-C" catalyst structure design for PMS activation and highlights the great interest of producing catalytic membranes for a confined treatment of organic pollutants from partial oxidation to complete mineralization as a new benchmark.

Interface engineered Ag-r-GO-CuFe2O4-Fe3O4 heterojunction an efficient photocatalyst for water treatment and toxicity study in Trifolium plants

Herein, we report the Ag-r-GO-CuFe2O4-Fe3O4 nanocomposite (Ag-r-GO-CFO-FO NCs) for effective photocatalytic activity against organic pollutants. Herein the O-S scheme mechanism is achieved by the formation of Ohmic (O) and Schottky (S) junctions. The two interfacial charge carriers for accelerated phono formation and mass transfer and thus increase in the light-harvesting with electron traps for the gerenation of reactive oxygen species (ROS). The photocatalytic activity of the constructed Ag-r-GO-CFO-FO NCs was tested against organic dyes (red RB, orange 2R and black B) and the degradation efficiency was calculated to be 99.8, 99.3 and 99.8% respectively. The radical quenching shows the formation of •OH and O2•- which plays major role in the mineralization of organic pollutants. Total organic carbon (TOC) after the degradation of red RB, orange 2R and black B by Ag-r-GO-CFO-FO NCs was 2.1%, 1.6% and 1.9% respectively, which shows the complete mineralization of the pollutants. In addition, the real-time application of the photocatalytic efficiency of NCs was performed against the effluent collected from dying industrial (which is a combination of red RB, orange 2R and black B) and the degradation efficiency was 98.2%. Toxicity of the NCs was performed against maize plants, the results show that the NCs are non-toxicity towards plants and can be used for real-time application. The efforts provide evidence of the combination of two interfacial charge carriers (O-S scheme) to boost the catalytic activity of the catalyst for water treatment.

Facile tuning Non-radical/Radical oxidation by nitrogen doping on Fe-S doped carbonaceous catalysts for peroxymonosulfate activation

In this paper, iron-sulfur-nitrogen co-doped carbonaceous materials (Fe@SxNyC) was prepared by doping N during the preparation of iron-sulfur co-doped carbonaceous material (Fe@SC), which was used to activate PMS and effectively modulate the radical and non-radical oxidation pathways in the catalytic system to achieve efficient degradation of sulfamerazine (SMR). N doping introduced multiple N sites (graphitic N, pyridinic N and pyrrolic N) in the Fe@SxNyC while promoting the generation of thiophene sulfur of the pristine active sites. Meanwhile, N doping introduced more defects in Fe@S4NC and thus exhibited better catalytic activity than Fe@SC, promoting the decomposition of PMS with a maximum k value (0.1721 min−1). Notably, the involvement of nitrogen shifted the cooperative oxidation reaction from a non-radical (1O2) to a radical-dominated (SO4·–) oxidation pathway with more oxidative intensity, resulting in deeper mineralization of organic pollutants. Moreover, compared with Fe@SC/PMS system, the radical-dominated Fe@S4NC/PMS system had better cycling stability, and the efficiency of SMR degradation could still reach 85 % after 4 cycles. The prepared Fe@S4NC catalytic ceramic membrane exhibited stable water flux and exceptional catalytic activity, demonstrating that Fe@S4NC had good potential for practical applications. This work elucidated the improvement of the catalytic mechanism of iron-carbon based materials by doping with various heteroatoms and provided a theoretical basis to design Fenton-like heterogeneous catalysts suitable for different water matrix.

Issues about application of bioremediation for cleaning up of contaminated sites

Bioremediation as a cleaning up technology is less predictable and efficient for application on site. An apparent gap is still evident between the laboratory results with pure culture or mixed culture of microorganisms and their biochemical capability including genes and enzymes involved, and the effectiveness at cleaning up the pollutants in soil and sediment on site. Associated issues include the characteristics of the site, ageing of the chemical pollutants and sequestration into soil as one, and activity and competitive of the degradative microorganisms under the actual contaminated conditions of natural environment. Because of these, the favorable conditions for the active growth of degradative microorganisms have not been investigated well enough with the available technology, so a simple inoculation of the pure culture effective under laboratory conditions cannot guarantee an expected efficiency and positive results at on site testing. In addition, the soil or sediment physical and chemical conditions under the natural environment play an important role in the removal or mineralization of organic pollutants, but inadequate attention has been given to these factors involved from ecology. It is the objectives here to bring the attention to the bioavailable concentration of the pollutants and also the active metabolism of the organisms in situ to advance and demonstrate the effective cleaning up of contaminated sites.

Fe/Au galvanic nanocells to generate self-sustained Fenton reactions without additives at neutral pH.

The generation of reactive oxygen species (ROS) via the Fenton reaction has received significant attention for widespread applications. This reaction can be triggered by zero-valent metal nanoparticles by converting externally added H2O2 into hydroxyl radicals (˙OH) in acidic media. To avoid the addition of external additives or energy supply, developing self-sustained catalytic systems enabling onsite production of H2O2 at a neutral pH is crucial. Here, we present novel galvanic nanocells (GNCs) based on metallic Fe/Au bilayers on arrays of nanoporous silica nanostructures for the generation of self-sustained Fenton reactions. These GNCs exploit the large electrochemical potential difference between the Fe and Au layers to enable direct H2O2 production and efficient release of Fe2+ in water at neutral pH, thereby triggering the Fenton reaction. Additionally, the GNCs promote Fe2+/Fe3+ circulation and minimize side reactions that passivate the iron surface to enhance their reactivity. The capability to directly trigger the Fenton reaction in water at pH 7 is demonstrated by the fast degradation and mineralization of organic pollutants, by using tiny amounts of catalyst. The self-generated H2O2 and its transformation into ˙OH in a neutral environment provide a promising route not only in environmental remediation but also to produce therapeutic ROS and address the limitations of Fenton catalytic nanostructures.

Interfacial engineering of a multijunctional In2O3/WO3@Ti4N3Tx S-scheme photocatalyst with enhanced photoelectrochemical properties.

Achieving high photoelectrochemical conversion efficiency requires the logical layout of a composite photocatalyst with optimal charge separation and transfer with ideal light harvesting capabilities to enhance the photocatalytic performance and the degradation rate towards organic pollutants. Herein, a novel In2O3/WO3@Ti4N3Tx S-scheme heterojunction was successfully synthesized and confirmed through valence band VB-XPS and Mott Schottky combined analysis. The formed MXene-doped In2O3/WO3@Ti4N3Tx S-scheme significantly enhances the charge flow and spatial separation with an improved oxidation and reduction ability. An in-built interfacial electric field at the WO3-In2O3 boundary enhanced the light-harvesting capacity, whereas Ti4N3Tx MXene offers a unique electron trapping effect which effectively lowers high charge carrier recombination rate-related photocatalytic deficit. It preserves the exceptional redox potency of the photocatalyst by providing a directed acceleration and effective separation of the photogenerated charges. A high carrier density (ND = 7.83 × 1021 cm-3) with a lower negative flat band (VFB = -0.064 V vs. Ag/AgCl) was obtained by Mott-Schottky analysis for 3 wt% In2O3/WO3@Ti4N3Tx, an indicator that a low overpotential is needed to activate photocatalytic reactions. This study, therefore, provides a novel thought for the design and fabrication of an S-scheme heterojunction for photocatalytic reactions for mineralization of organic pollutants in water and clean energy production.

Fabrication of 2D graphene oxide incorporating S-scheme Sn2S3–In2S3 heterojunctions for enhanced photocatalytic mineralization of organic pollutants

Harnessing solar energy using semiconductor-based materials to generate charge pairs to effectively drive photo-redox reactions has been envisioned as a promising approach toward a sustainable future.

Differences among active toluene-degrading microbial communities in farmland soils with different levels of heavy metal pollution.

Heavy metals can severely influence the mineralisation of organic pollutants in a compound-polluted environment. However, to date, no study has focused on the effects of heavy metals on the active organic pollutant-degrading microbial communities to understand the bioremediation mechanism. In this study, toluene was used as the model organic pollutant to explore the effects of soils with different levels of heavy metal pollution on organic contaminant degradation in the same area via stable isotope probing (SIP) and 16S rRNA high-throughput sequencing. Heavy metals can seriously affect toluene biodegradation and regulate the abundance and diversity of microbial communities. SIP revealed a drastic difference in the community structure of active toluene degraders between the unpolluted and heavy metal-polluted soils. All SIP-identified degraders were assigned to nine bacterial classes, among which Alphaproteobacteria, Gammaproteobacteria, and Bacilli were shared by both treatments. Among all active degraders, Nitrospira, Nocardioides, Conexibacteraceae, and Singulisphaera were linked to toluene biodegradation for the first time. Notably, the type of active degrader and microbial diversity were strongly related to biodegradation efficiency, indicating their key role in toluene biodegradation. Overall, heavy metals can affect the microbial diversity and alter the functional microbial communities in soil, thereby influencing the removal efficiency of organic contaminants. Our findings provide novel insights into the biodegradation mechanism of organic pollutants in heavy metal-polluted soils and highlight the biodiversity of microbes involved in toluene biodegradation in compound-polluted environments.

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.

In situ electrogenerated Cu(III) triggers hydroxyl radical production on the Cu-Sb-SnO2 electrode for highly efficient water decontamination

The electrochemical oxidation process has the unique advantage of in-situ •OH generation for deep mineralization of organic pollutants, which is expected to provide a solution for the globally decentralized wastewater treatment and reuse. However, it is still a great challenge to develop low-cost anodes with ultrahigh •OH yield and low energy consumption. Here, a low-cost and stable mixed metal oxide (MMO) anode (Cu-Sb-SnO2) developed by a simple and scalable preparation process presents extremely high organic pollutants degradation efficiency and low energy consumption. The tetracycline degradation kinetics constant of the Cu-Sb-SnO2 system (0.362 min-1) was 9 to 45 times higher than that of other prepared anodes, which is superior to the existing anodes reported so far. The experimental results and theoretical calculations indicate that the Cu-Sb-SnO2 has moderate oxygen evolution potential, larger water adsorption energy, and lower reaction energy barrier, which is conducive to selective water oxidation to generate •OH. Notably, it is systematically and comprehensively confirmed that the generation of •OH triggered by in situ electrogenerated Cu(III) increased •OH steady-state concentration by over four times. Furthermore, the doped Cu species can play a key role in promoting charge transfer as an "electronic porter" between Sn and Sb in the electrocatalytic process by adjusting the electronic structure of the Sb-SnO2 electrode. This work paves the way for the development of MMO anodes utilizing the advantage of the Cu redox shuttle.

Anchoring SrTiO3 nanoparticles on layered ZnIn2S4 to construct S-scheme heterojunctions as novel photocatalysts for efficient degradation of MO dye

Water pollution can be efficiently treated by semiconductor photocatalysts under sunlight irradiation. In this study, novel S-scheme SrTiO3/ZnIn2S4 composites were successfully fabricated via a facile oil-bath method. And the synthesized samples were then characterized by various characterization techniques together with Density Functional Theory (DFT) calculation. The X-Ray Diffraction(XRD)patterns show that SrTiO3/ZnIn2S4 composites are composed of cubic perovskite structure SrTiO3 and hexagonal phase ZnIn2S4. The High Resolution Transmission Electron Microscope(HRTEM)and Field Emission Scanning Electron Microscope (FESEM) images showed the intimate contacts between SrTiO3 and ZnIn2S4 are established to form the heterojunction. The photocatalytic activity of the composite was excellent when degrading organic pollutants, which outperformed that of pristine SrTiO3 and ZnIn2S4. The prepared SrTiO3/ZnIn2S4-33% composite sample was proved to have the best photocatalytic activity, with 98 % degradation of organic pollutants under 32 min. The ·O2– is the main active reaction species for the degradation of organic pollutants, which was demonstrated by free radical trapping experiment. In addition, the mineralization of organic pollutants during the degradation process was analyzed by Total Organic Carbon (TOC) test. According to a series of experimental and theoretical calculations, the S-scheme heterojunction formed in the SrTiO3/ZnIn2S4 composite is put forward for comprehending the photocatalytic degradation of organic pollutants and the formation of free radicals.

Plasmonic photocatalytic degradation of tebuconazole and 2,4-dichlorophenoxyacetic acid by Ag nanoparticles-decorated TiO2 tracked by SERS analysis

Chemical oxidation technologies have been notably used for the mineralization of organic pollutants from aqueous effluents, been especially relevant for the degradation of pesticides. In this context, both tebuconazole (TEB) and 2,4-dichlorophenoxyacetic acid (2,4-D) pesticides were photodegraded by a combined catalyst of TiO2 and silver nanoparticles irradiated by UV-A light (λmax = 368 nm), and the experiments were tracked by surface-enhanced Raman scattering (SERS) spectroscopy. For 2,4-D, the degradation of about 70% was observed after almost 200 min, while for TEB, a decrease of 80% of the initial concentration was observed after approximately 100 min. The SERS monitoring allowed the proposal of some by-products, such as oxidized aliphatic chain and triazole from TEB besides glycolic, glyoxylic and dihydroxyacetic acids from 2,4-D. Their toxicities were predicted through ECOSAR software, verifying that most of them were not harmful to populations of fish, Daphnia and green algae. Thus, the performed oxidative process was efficient in the photodecomposition of TEB and 2,4-D pesticides, inclusive in terms of the decreasing of the toxicity of contaminated effluents.