Phenol degradation in waters with high iodide level by layered double hydroxide-peroxodisulfate: Pathways and products.

Recently, layered double hydroxide-peroxodisulfate (LDH-PDS) as an advanced oxidation system can effectively remove organics by the pathway of free radical. However, little has been known if there is a potential risk regarding the formation of high toxic iodine byproducts through another pathway when LDH-PDS is used in high iodide waters at coastal areas. Therefore, this study investigated phenol degradation pathways and transformation products to evaluate both removal mechanism and potential risk by LDH-PDS in high iodide waters. The results showed that in LDH-PDS system, with the degradation of PDS, phenol degraded till below detection limit in 1 hr in the presence of iodide, while PDS and phenol were hardly degraded in the absence of iodide, indicating iodide accelerated the transformation of PDS and the degradation of phenol. What is more, it reached the highest phenol removal efficiency under the condition of 100 mg/L LDH, 0.1 mmol/L PDS and 1.0 mmol/L iodide. In LDH-PDS system, iodide was rapidly oxidized by the highly active interlayer PDS, resulting in the formation of reactive iodine including hypoiodic acid, iodine and triiodide instead of free radicals, which contributed rapid degradation of phenol. However, unfortunately toxic iodophenols were detected. Specifically, 2-iodophenol and 4-iodophenol were formed firstly, afterwards 2,4-diiodophenol and 2,6-diiodophenol were produced, and finally iodophenols and diiodophenols gradually decreased and 2,4,6-Triiodophenol were produced. These results indicated that LDH-PDS should avoid to use in high iodide waters to prevent toxic iodine byproduct formation although iodide can accelerate phenol degradation.

A ratiometric electrochemiluminescent immunoassay for calcitonin by using N-(aminobutyl)-N-(ethylisoluminol) and graphite-like carbon nitride.

A ratiometric electrochemiluminescent (ECL) assay is described for the determination of the calcium(II) regulator calcitonin (CT). The method is making use of (a) graphite-like carbon nitride (g-C3N4) as the cathodic luminophore, (b) N-(aminobutyl)-N-(ethylisoluminol) (ABEI) as the anodic luminophore, and (c) peroxodisulfate and dissolved oxygen as coreactants. The luminous potential of g-C3N4 and ABEI can be well distinguished because of their different luminescent properties. Energy transfer between g-C3N4 and ABEI is not observed, and the coreactants peroxodisulate and oxygen do not interfere with each other. Au nanoparticles were functionalized with g-C3N4 and placed on the electrode to serve as a matrix for immobilization of primary antibody (Ab1). In the presence of CT, it will bind to the electrode. Then secondary antibody (Ab2) modified with polyaniline (PANI) and ABEI is incubated onto the electrode. With the increase in the concentration of CT, the blue ECL of g-C3N4 is quenched by PANI, while the blue luminescence of ABEI is enhanced. This enables ratiometric detection of calcitonin by ratioing the internsities at 460 and 475 nm. Response is linear in the 0.1~40 pg·mL-1 CT concentration range, and the limit of detection is 23 fg·mL-1. The method breaks the limitation of common ECL ratiometric strategy, namely, two luminophores often share the common coreactant. Graphical abstractSchematic representation of an immunoassay where polyaniline (PANI) in a BSA-Ab2-ABEI-Au@PANI composite quenches the cathodic signal of a graphitic carbon nitride (Au-g-C3N4) modified with gold nanoparticles (Au), while N-(aminobutyl)-N-(ethylisolumino) (ABEI) in the BSA-Ab2-ABEI-Au@PANI composit produces an anodic signal that enables quantitation of calcitonin.

Electrochemiluminescent immunoassay for the lung cancer biomarker CYFRA21-1 using MoOx quantum dots.

Molybdenum oxide quantum dots (MoOx QDs) were synthesized by a one-pot method and used as a versatile probe in an electrochemiluminescent (ECL) immunoassay of the non-small cell lung cancer biomarker cytokeratin 19 fragment 21-1 (CYFRA21-1) as a model analyte. The MoOx QDs exhibited stable and strong cathodic green ECL, with an emission peak at 535 nm, in the presence of K2S2O8 within the potential range of -2.0 to 0 V. On exposure to CYFRA21-1, the ECL decreases because of the immunoreaction between CYFRA21-1 and its antibody which generates a barrier for electron transfer. The determination of CYFRA21-1 with favorable analytical performances was successfully realized under the optimal conditions. ECL decreases linearly in the 1 pg mL-1 to 350 ng mL-1 CYFRA21-1 concentration range, and the detection is as low as 0.3 pg mL-1. Excellent recoveries from CYFRA21-1-spiked human serum indicate that the assay can be operated under physiological conditions. Graphical abstractSchematic representation of the fabrication of molybdenum oxide quantum dots (MoOx QDs) and the electrochemiluminescent (ECL) immunoassay based on the use of the MoOx QDs ECL probe for cytokeratin 19 fragment 21-1 (CYFRA21-1).

Persulfate activation with biochar supported nanoscale zero- valent iron: Engineering application for effective degradation of NCB in soil.

Nitrochlorobenzene (NCB) is very common in pesticide and chemical industries, which has become a major problem in soil environment. However, the remediation of NCB contaminated soil is received finite concern. Using biochar as a substrate for nanoscale-zero valent iron (nZVI/p-BC) to activate peroxodisulfate (PDS), a novel heterogeneous oxidative system had been applied in the current study to remediate NCB contaminants in soil. The degradation efficiencies and kinetics of m-NCB, p-NCB, and o-NCB by various systems were contrasted in soil slurry. Key factors including the dosage of nZVI/p-BC, the molar ratio of nZVI/PDS, initial pH and temperature on degradation of NCB were further examined. The results confirmed that the nZVI/p-BC/PDS displayed the remarkable performance for removing NCB compared with other systems. Higher temperature with nZVI/PDS molar ratio of 2:1 under the acidic condition favored the reduction of NCB. The treatment for NCB with optimal conditions were evaluated for the engineering application. The mechanism of nZVI/p-BC/PDS indicated that electron transfer between p-BC and nZVI was responsible for activation of PDS, generating active species (SO4•-, •OH and 1O2) via both the free and non-free radical pathways. Experimental results revealed prominent availability of nZVI/p-BC/PDS system in remediation of actual contaminated field by NCB.

Efficient treatment of old landfill leachate by peroxodisulfate assisted electro-oxidation and electro-coagulation combined system.

Efficient removal of chemical oxygen demand (COD) and ammonium-N (NH4+-N) is the key issue for treatment of old landfill leachate. In this study, a peroxodisulfate assisted electro-oxidation and electro-coagulation coupled system (POCS) adopting Ti/SnO2-Sb2O3/TiO2 and Fe dual-anode was constructed for synergistic removal of COD and NH4+-N in old landfill leachate. Laboratory experiment results showed that with current density of 20 mA cm-2, initial pH value of 8.0 and peroxodisulfate (PDS) concentration of 60 mM, the POCS system can reach removal efficiencies of 84.2% for COD and 39.8% for NH4+-N. The POCS effectively reduced the complexity of macromolecular organics and avoided the need to add acid or base to adjust pH value. The residual NH4+-N could be effectively recovered through struvite precipitation with a 93.8% purity of the precipitate.

Comparative study of reactive oxygen species and tetracycline degradation pathways in catalytic peroxodisulfate activation by asymmetric mesoporous TiO2 and the corresponding controlled-release materials.

The removal of trace amounts of antibiotics from water environments while simultaneously avoiding potential environmental hazards during the treatment is still a challenge. In this work, green, harmless, and novel asymmetric mesoporous TiO2 (A-mTiO2) was combined with peroxodisulfate (PDS) as active components in a controlled-release material (CRM) system for the degradation of tetracycline (TC) in the dark. The formation of reactive oxygen species (ROS) and the degradation pathways of TC during catalytic PDS activation by A-mTiO2 powder catalysts and the CRMs were thoroughly studied. Due to its asymmetric mesoporous structure, there were abundant Ti3+/Ti4+ couples and oxygen vacancies in A-mTiO2, resulting in excellent activity in the activation of PDS for TC degradation, with a mineralization rate of 78.6%. In CRMs, ROS could first form during PDS activation by A-mTiO2 and subsequently dissolve from the CRMs to degrade TC in groundwater. Due to the excellent performance and good stability of A-mTiO2, the resulting constructed CRMs could effectively degrade TC in simulated groundwater over a long period (more than 20 days). From electron paramagnetic resonance analysis and TC degradation experiments, it was interesting to find that the ROS formed during PDS activation by A-mTiO2 powder catalysts and CRMs were different, but the degradation pathways for TC were indeed similar in the two systems. In PDS activation by A-mTiO2, besides the free hydroxyl radical (·OH), singlet oxygen (1O2) worked as a major ROS participating in TC degradation. For CRMs, the immobilization of A-mTiO2 inside CRMs made it difficult to capture superoxide radicals (·O2-), and continuously generate 1O2. In addition, the formation of sulfate radicals (·SO4-), and ·OH during the release process of CRMs was consistent with PDS activation by the A-mTiO2 powder catalyst. The eco-friendly CRMs had a promising potential for practical application in the remediation of organic pollutants from groundwater.

Efficient degradation of norfloxacin using a novel biochar-supported CuO/Fe3O4 combined with peroxydisulfate: Insights into enhanced contribution of nonradical pathway.

Nonradical persulfate oxidation techniques have evolved as a new contaminated water treatment approach due to its great tolerance to water matrixes. The catalysts of CuO-based composites have received much attention in that aside from SO4•-/•OH radicals, the nonradicals of singlet oxygen (1O2) can be also generated during persulfate activation via CuO. However, the issues regarding particles aggregation and metal leaching from the catalysts during the decontamination process remain to be addressed, which could have a remarkable impact on the catalytic degradation of organic pollutants. Accordingly in the present study, a novel biochar-supported bimetallic Fe3O4-CuO catalyst (CuFeBC) was facilely developed to activate peroxodisulfate (PDS) for the degradation of norfloxacin (NOR) in aqueous solution. The results showed CuFeBC has a superior stability against metal ions Cu/Fe leaching, and NOR (30 mg L-1) was degraded at 94.5% within 180 min in the presence of CuFeBC (0.5 g L-1) and PDS (6 mM) in pH 8.5. The scavenging of reactive oxygen species and electron spin resonance analysis revealed that 1O2 dominated the degradation of NOR. Compared with pristine CuO-Fe3O4, the interaction between biochar substrate and metal particles could significantly enhance the contribution of the nonradical pathway to NOR degradation from 49.6% to 84.7%. Biochar substrate could efficiently reduce the leaching of metal species from the catalyst, thereby maintaining excellent catalytic activity and lasting reusability of the catalyst. These findings could enlighten new insights into fine-tuning radical/nonradical processes from CuO-based catalysts for the efficient remediation of organic contaminants in polluted water.

Stability performance analysis of Fe based MOFs for peroxydisulfates activation to effectively degrade ciprofloxacin.

Fe-based metal-organic frameworks (MOFs) show high activity toward the activation of peroxodisulfate (PDS) for the removal of organic micropollutants (OMPs) in wastewater treatment. However, there is a phenomenon of Fe ion dissolution in the Fe-based MOFs' active PDS system, and the reasons and influencing factors that cause Fe ion dissolution are poorly understood. In this study, we synthesized four types of Fe-based MOFs and confirmed their crystal structure through characterization. All types of Fe-based MOFs were found to activate PDS and form sulfate radicals (SO4 -), which effectively remove OMPs in wastewater. During the process of Fe-based MOFs activating PDS for CIP removal, activated species, oxidant reagent, and pH negatively impact the stability performance of the MOFs' structure. The coordination bond between Fe atom and O atom can be attacked by water molecules, free radicals, and H+, causing damage to the crystal structure of MOFs. Additionally, Fe (II)-MOFs exhibit the best stability performance, due to the enhanced bond energy of the coordination bond in MOFs by the F ligands. This study summarizes the influencing factors of Fe-based MOFs' damage during PDS activation processes, providing new insights for the future development of Fe-based MOFs.

Magnetized algae catalyst by endogenous N to effectively trigger peroxodisulfate activation for ultrafast degraded sulfathiazole: Radical evolution and electron transfer.

An innovative Fe-N co-coupled catalyst MN-2 was prepared from waste spirulina by co-pyrolysis as a highly active carbon-based catalyst for the activation of peroxydisulfate (PDS) for the degradation of sulfathiazole (ST). The protein-rich raw material Spirulina provided sufficient N during the pyrolysis process, thus achieving N doping without an additional nitrogen source, optimizing the interlayer structure of the biochar material and effectively inhibiting the leaching of the ligand metal Fe. MN-2 showed highly efficient catalytic activity for peroxydisulfate (PDS), with a degradation efficiency of 100% for ST within 30 min and a kinetic constant (kobs) reached 0.306 min-1, benefiting from the excellent adsorption ability of MN-2 forming MN-2-PDS* complexes and the electron transfer process generated by Fe3+ and Fe2+ cycling, oxygen-containing functional groups. The effects of PDS dosage, initial pH and coexisting anions on the oxidation process were also investigated. Free radical quenching, electron paramagnetic resonance and electrochemical measurements were employed to explain the hydroxyl (·OH) and sulfate (SO4·-) as the dominant active species and the electron transfer effect on the removal of ST. MN-2 maintained a ST removal rate of 84% after four recycling experiments, showing a high reusability performance. This work provides a simple way to prepare magnetized N-doped biochar, a novel catalyst (MN-2) for efficient activation of PDS for ST degradation, and a feasible method for removing sulfanilamide antibiotics in water environment.

Electrochemical-assisted ultraviolet light coupled peroxodisulfate system to degrade ciprofloxacin in water: Kinetics, mechanism and pathways.

The persulfate advanced oxidation is an emerging and efficient pollutant treatment method, but usually requires the help of other materials or energy to catalyze and produce highly oxidizing active substances. In this paper, electrochemical-assisted ultraviolet light coupled peroxodisulfate system (E-UV-PDS) was used to degrade ciprofloxacin (CIP), and it was determined that electrolysis and ultraviolet photolysis were synergistic by calculation. The effects of initial pH, voltage, peroxodisulfate dosage, CIP concentration and coexisting anions on the degradation process were explored. The quenching experiments showed that 1O2, ⋅OH and SO4-⋅ were the main active oxygen species. Under the following conditions, ultraviolet light = 6 W, voltage = 4 V, [peroxodisulfate] = 20 mM, [pH]0 = 7 and [CIP] = 100 mgL-1, the degradation rate of CIP reached about 100% after 120 min, and the influence of inorganic anions was also discussed. Several intermediate products were identified by LC-MS, and three degradation pathways were speculated for CIP degradation. Finally, economic evaluation of the E-UV-PDS system was made, and it was useful to construct environmentally friendly and low-cost catalytic processes for the efficient degradation of organic pollutants.

UV-assisted nitrogen-doped reduced graphene oxide/Fe3O4 composite activated peroxodisulfate degradation of norfloxacin.

We reported the preparation of NGO-Fe3O4 by simple hydrothermal-co-precipitation. The catalysts were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy (FTIR). It was demonstrated that norfloxacin (NOR) could be effectively degraded by the UV/NGO-Fe3O4/PDS system. The degradation efficiency reached 100% within 13 min (the concentration of NOR and S2O82- were 100 mg L-1 and 1 mM, respectively; m(NGO-Fe3O4): m(PDS) = 4: 1; pH: 3.0). In addition, NGO-Fe3O4 showed stable catalytic activity in recycling. The analysis found that the in-situ generated ·OH was the main active free radicals but SO4-⋅ also participated in the NOR degradation. Based on the identified intermediates, the NOR degradation pathways were proposed with UV/NGO-Fe3O4/PDS system.

Influence of thermally activated peroxodisulfate pretreatment on gaseous emission, dissolved organic matter and maturity evolution during spiramycin fermentation residue composting.

Aerobic composting combined with appropriate pretreatment is promising to achieve the utilization of antibiotics fermentation residues (AFRs). This research studied the effect of thermally activated peroxodisulfate (TAP) pretreatment on greenhouse gas (GHGs) emission, dissolved organic matter (DOM) and maturity evaluation during spiramycin fermentation residue (SFR) composting. Three treatments were conducted from co-composting of SFR and wheat straw, while 90% and 99.9% residual spirmycin removal pretreatment SFR by TAP were provided and compared with raw SFR. The cumulative CO2 and NH3 emissions increased by 17.2% and 30.8% after TAP pretreatment removed 99.9% residual spiramycin in SFR, while the cumulative CH4 and N2O emission decreased by 34.0% and 5.27%, respectively. The DOM, humic acid (HA)/fulvic acid (FA) and NH4+/NO3- analysis confirmed that the composting maturity was improved with the increasing of HA and NO3- content by TAP pretreatment.

Insights into the synergetic mechanism of a combined vis-RGO/TiO2/peroxodisulfate system for the degradation of PPCPs: Kinetics, environmental factors and products.

In recent years, how to effectively remove emerging organic pollutants in water bodies has been studied extensively, especially in the actual complex water environment. In the present study, an effective wastewater treatment system that combined photocatalysis and an oxidizing agent was investigated. Specifically, visible-light driven reduced graphene oxide (RGO)/TiO2 composites were prepared, and peroxodisulfate (PDS) was used as electron acceptor to accelerate the photocatalytic activity of this material. The vis-RGO/TiO2/PDS system exhibited outstanding properties in the degradation of diclofenac (DCF), which was also facilitated by acidic conditions and Cl-. Lake water, tap water, river water and HCO3- decreased the DCF degradation rate, while NO3- affected the system only slightly. Low concentrations of fulvic acid (FA) promoted the degradation of DCF via the generation of excited states, whereas a high concentration of FA inhibited the degradation, which was likely due to the light screening effect. The photocatalytic mechanism revealed that PDS served as an electron acceptor for the promotion of electron-hole pair separation and the generation of additional reactive oxygen species, while the RGO served as an electric conductor. The active substances, h+, OH, 1O2, SO4- and O2- were generated in this system, O2- and h+ played significant roles in the degradation of DCF based electron spin resonance tests and radical quenching results. According to the mass spectrometry results, the amide bond cleavage, dechlorination reaction, hydroxyl addition reaction, and decarboxylation reaction were the primary transformative pathways.

Effect of peroxomonosulfate, peroxodisulfate and hydrogen peroxide on graphene oxide photocatalytic performances in methyl orange dye degradation.

Carbocatalyst GO photocatalytic mechanism and performances in the presence of an electron scavenger (ES) has been consciously discussed herein. Single layer GO photocatalyst has been synthesized by Hummer's method and photocatalyst characteristics are gathered by different analytical methods. Studies ensured the formation of a good crystalline GO that contains number of oxygenated functional groups, with average crystalline size of the sp2 domain in 18.24 nm. Optical studies suggest that optical band gap of the GO nanosheet photocatalyst is found in the range of 3.19-4.4 eV. TEM analysis confirms the formation of a single layer GO nanosheet. Photocatalytic study justifies that in the absence of ES, 24% mineralization efficiency is achieved with GO as a photocatalyst, whereas in the presence of ES such as PMS, PDS and HP the mineralization efficiency is considerably enhanced up to 91%, 77% and 65% respectively. Moreover, photocatalytic degradation intermediate byproducts were also examined through LC-MS analysis. The study substantiates methyl orange dye degradation undergoes via the multiple degradation pathway such as (i) azo bond cleavage and hydroxylation, (ii), asymmetric cleavage followed by reduction of sulfonate group and aromatic ring removal and (iii) consecutive demethylation reactions and sulfonate group removal. Rationalized the contributing effects of process parameters towards the photocatalytic degradation of methyl orange using a RSM based on CCD validation. The validation reveals that most significant process parameter affects degradation process are the irradiation time, catalyst loading and choice of ES.

Three phenanthroline-metal complexes with topologically similar but geometrically different conformations.

The structures of three related complexes of general formula M(pds)(nab)2 [pds is the peroxodi-sulfate anion and nab is an nitro-gen-containing aromatic base], viz. bis(2,9-dimethyl-1,10-phenanthroline-κ2N,N')(peroxodi-sulfato-κ2O,O')cadmium, [Cd(S2O8)(C14H12N2)2], (V), bis-(3,4,7,8-tetra-methy-1,10-phenanthroline-κ2N,N')(peroxodi-sulfato-κ2O,O')zinc, [Zn(S2O8)(C16H16N2)2], (VI), and bis-(3,4,7,8-tetra-methy-1,10-phenanthroline-κ2N,N')(peroxodi-sulfato-κ2O,O')cadmium, [Cd(S2O8)(C16H16N2)2], (VII), present the same topological coordination, with three chelating ligands in an MN4O2 polyhedron. The main difference resides in the fact that the first two complexes are bis-ected by a crystallographic twofold axis, thus providing a symmetrical environment to the cation, while in the third one this symmetry is disrupted into a clearly unsymmetrical disposition, probably by way of an unusually strong intra-molecular C-H⋯O hydrogen bond. The situation is compared with similar inter-actions in the literature. The structure of (V) is based on a redetermination in the correct space group C2/c of the structure originally described in the Cc space group [Harvey et al. (2001). Aust. J. Chem.54, 307-311; Marsh (2004 ▸). Acta Cryst. B60, 252-253].

Surface Surgery of the Nickel-Rich Cathode Material LiNi0.815Co0.15Al0.035O2: Toward a Complete and Ordered Surface Layered Structure and Better Electrochemical Properties.

A complete and ordered layered structure on the surface of LiNi0.815Co0.15Al0.035O2 (NCA) has been achieved via a facile surface-oxidation method with Na2S2O8. The field-emission transmission electron microscopy images clearly show that preoxidation of the hydroxide precursor can eliminate the crystal defects and convert Ni(OH)2 into layered ß-NiOOH, which leads to a highly ordered crystalline NCA, with its (006) planes perpendicular to the surface in the sintering process. X-ray photoelectron spectroscopy and Raman shift results demonstrate that the contents of Ni2+ and Co2+ ions are reduced with preoxidization on the surface of the hydroxide precursor. The level of Li+/Ni2+ disordering in the modified NCA determined by the peak intensity ratio I(003)/I(104) in X-ray diffraction patterns decreases. Thanks to the complete and ordered layered structure on the surface of secondary particles, lithium ions can easily intercalate/extract in the discharging-charging process, leading to greatly improved electrochemical properties.

Hirshfeld surface analysis of the 1,1'-(ethane-1,2-diyl)dipyridinium dication in two new salts: perchlorate and peroxodisulfate.

In the title salts, C12H14N2(2+)·2ClO4(-), (I), and C12H14N2(2+)·S2O8(2-), (II), the dication is organized around an inversion centre located at the centre of the -CH2CH2- bridge and the two pyridine segments are anti with respect to one another. The peroxodisulfate anion in (II) also exhibits inversion symmetry. Hirshfeld surface analysis shows closely similar Hirshfeld surface shapes for the dications in the two salts, reflecting similar intermolecular contacts and similar conformations. The two-dimensional fingerprint plots (FPs) are quite asymmetric, due to the presence of more than one component (cation and anion). The most striking of the complementary features for each of the FPs of the dications is the broad green spike in the region d(e) > d(i), without the presence of a corresponding spike in the region d(e) < d(i), reflecting the absence of O···H contacts. Moreover, H···O interactions (51% in the dications of both salts) outnumber other contacts in both crystal structures.

Visible light-induced decomposition of a fluorotelomer unsaturated carboxylic acid in water with a combination of tungsten trioxide and persulfate.

Photochemical decomposition of a fluorotelomer unsaturated carboxylic acid, C3F7CFCHCOOH (1), in the presence of WO3 and an electron acceptor (S2O8(2-) or H2O2) in water under visible-light irradiation was investigated. Under an O2 atmosphere, 1 was not decomposed either by TiO2 (P25) or WO3 alone. A combination of WO3 and H2O2 also resulted in almost no decomposition of 1. In contrast, irradiation in the presence of a combination of WO3 and S2O8(2-) (potassium salt) efficiently decomposed 1 to F(-), CO2, C3F7COOH, and C2F5COOH. The decomposition of 1 was affected by the counter cation of S2O8(2-): the decomposition extent was higher with K2S2O8 than with (NH4)2S2O8. The decomposition of 1 was further enhanced when the reaction in the presence of WO3 and K2S2O8 was carried out under an argon atmosphere. Under O2, the amount of H2O2 formed in the reaction solution was an order of magnitude higher than the amount formed under argon. This fact suggests that the decrease in the decomposition of 1 under O2 can be ascribed to the formation of H2O2, which consumed S2O8(2-) and SO4(-).

Comparative study of the photodegradation of bisphenol A by HO(•), SO4(•-) and CO3(•-)/HCO3 radicals in aqueous phase.

The aim of this study was to determine the effectiveness of oxidation processes based on UV radiation (UV, UV/H2O2, UV/K2S2O8, and UV/Na2CO3) to remove bisphenol A (BPA) from aqueous solution. Results showed that UV radiation was not effective to remove BPA from the medium. The addition of radical promoters such as H2O2, K2S2O8, or Na2CO3 markedly increased the effectiveness of UV radiation through the generation of HO(•), SO4(•-), or CO3(•-)/HCO3(•) radicals, respectively. The reaction rate constants between BPA and HO(•), SO4(•-), and CO3(•-)/HCO3(•) radicals were k(HO(•)BPA)=1.70±0.21×10(10)M(-1)s(-1), k(SO4(•-)BPA)=1.37±0.15×10(9)M(-1)s(-1) and k(CO3(•-)/HCO3(•)BPA)=3.89±0.09×10(6)M(-1)s(-1), respectively. The solution pH had a major effect on BPA degradation with the UV/H2O2 system, followed by UV/K2S2O8, and UV/Na2CO3 systems. All oxidation systems in this study showed 100% effectiveness to remove BPA from wastewater, due to its large content of natural organic matter (NOM), which can absorb UV radiation and generate excited triplet states ((3)NOM*) and various reactive oxygen species. With all three systems, the total organic carbon in the medium was markedly decreased after 5 min of treatment. The toxicity of byproducts was higher than that of BPA when using UV/H2O2, similar to that of BPA with the UV/Na2CO3 system, and lower than that of BPA after 40 min of treatment with the UV/K2S2O8 system.