A facile strategy for photocatalytic degradation of seven neonicotinoids over sulfur and oxygen co-doped carbon nitride.

Mounting evidence highlights the negative impacts of neonicotinoids on non-target organisms and ecosystem, yet there are a few of methods to address the residual neonicotinoids in environment. Herein, series of sulfur and oxygen co-doped carbon nitride (SOCNx) were successfully synthesized via one-step thermal polymerization and applied in photodegradation of multi-neonicotinoids (dinotefuran, acetamiprid, clothianidin, thiacloprid, imidacloprid, nitenpyram and thiamethoxam) simultaneously for the first time. Unique tubular structure was observed at the specific doping ratio, which enhanced both mass transfer and specific surface area of graphitic carbon nitride (g-C3N4). The doping process changed the morphology of g-C3N4 materials and also affected its photocatalytic performance. The degradation rate of optimized material (SOCN8) for nitenpyram could surpass 90% just in 30 min under visible light in aqueous matrix. The degradation for target insecticide increased maximum efficiency of 57.6% compared to bulk g-C3N4. Moreover, the possible mechanism of the degradation process was proposed. The results revealed that photon-induced hole (h+) was the primary active species during the degradation of seven investigated neonicotinoids. Moreover, the SOCN8 showed excellent recyclability after four consecutive cycles, which implied promising applications for pesticide-contaminated water remedy.

Fabrication of smart stimuli-responsive mesoporous organosilica nano-vehicles for targeted pesticide delivery.

It is highly desirable to construct stimuli-responsive nanocarriers for improving pesticides targeting and preventing the pesticides premature release. In this work, a novel redox and α-amylase dual stimuli-responsive pesticide delivery system was established by bonding functionalized starch with biodegradable disulfide-bond-bridged mesoporous silica nanoparticles which loaded with avermectin (avermectin@MSNs-ss-starch nanoparticles). The results demonstrated that the loading capacity of avermectin@MSNs-ss-starch nanoparticles for avermectin was approximately 9.3 %. The starch attached covalently on the mesoporous silica nanoparticles could protect avermectin from photodegradation and prevent premature release of active ingredient. Meanwhile, the coated starch and disulfide-bridged structure of nanoparticles could be decomposed and consequently release of the avermectin on demand when nanoparticles were metabolized by glutathione and α-amylase in insects. The bioactivity survey confirmed that avermectin@MSNs-ss-starch nanoparticles had a longer duration in controlling Plutella xylostella larvae compared to avermectin emulsifiable concentrate. In consideration of the superior insecticidal activity and free of toxic organic solvent, this target-specific pesticide release system has promising potential in pest management.

UV-C light irradiation enhances toxic effects of chlorpyrifos and its formulations.

UV-C irradiation is widely used in the food industry. However, the health effects from dietary exposure to the irradiated pesticide residues retained in foodstuffs are underestimated. In this study, technical chlorpyrifos (TCPF) and its oil in water (EW) and emulsifiable concentrate (EC) formulations were irradiated by UV-C, and their photodegradation products were subjected to toxicity assessment, including determination of acetylcholinesterase (AChE) activity, genotoxicity and oxidative stress using human blood cells as a model system. Toxicity studies were performed using the chlorpyrifos concentrations in the range of those proposed as the maximum residue levels in plant commodities. TCPF, EW and EC photodegradation products induced DNA damage and oxidative stress, and their genotoxicity did not decrease as a function of irradiation time. Irradiated TCPF and EC are more potent AChE inhibitors than irradiated EW. Accordingly, the application of UV-C irradiation must be considered when processing the plants previously treated with chlorpyrifos formulations.

Improvement of Vip3Aa16 Toxin Production and Efficiency Through Nitrous Acid and UV Mutagenesis of Bacillus thuringiensis (Bacillales: Bacillaceae).

Bacillus thuringiensis Berliner (Bacillales: Bacillaceae) strain BUPM95 was known by the efficiency of its vegetative insecticidal protein (Vip3Aa16) against different Lepidoptera such as Spodoptera littoralis (Lepidoptera: Noctuidae). To overcome the problem of the low quantities of Vip3 proteins secreted by B. thuringiensis strains in the culture supernatant, classical mutagenesis of vegetative cells of BUPM95 strain was operated using nitrous acid and UV rays. The survivors were screened on the basis of their hemolytic activity and classified in three groups: unaffected, overproducing, and hypo-producing mutants. Using different mutants improved in their hemolytic activity, the supernatants showed an improved toxicity toward S. littoralis larvae (83.33-100% of mortality) compared with the wild-type supernatant (76%). After Vip3 protein quantification in the different supernatants, bioassays against S. littoralis larvae demonstrated that mutants M62, M43, and M76 were improved in the efficiency of their toxin as demonstrated by the lower values of LC50 and LC90 compared with the wild-type Vip3Aa16 protein. However, M26 and M73 mutants were improved in the toxin quantities produced in the supernatant. The improvement of the production and the efficiency of B. thuringiensis Vip3 toxins should contribute to a significant reduction of the production costs of these very interesting B. thuringineis proteins and facilitate the use of these toxins in the pest control management.

Antioxidative cellular response of lepidopteran ovarian cells to photoactivated alpha-terthienyl.

Photodynamic sensitizers as useful alternative agents have been used for population control against insect pests, and the response of insect ovarian cells towards the photosensitizers is gaining attention because of the next reproduction. In this paper, antioxidative responses of lepidopteran ovarian Tn5B1-4 and Sf-21 cells to photoactivated alpha-terthienyl (PAT) are investigated. PAT shows positive inhibitory cytotoxicity on the two ovarian cells, and its inhibition on cell viability is enhanced as the concentrations are increased and the irradiation time is extended. Median inhibitory concentrations (IC50) are 3.36µg/ml to Tn5B1-4 cells, and 3.15µg/ml to Sf-21 cells at 15min-UV-A irradiation 2h-dark incubation. Under 10.0µg/ml PAT exposure, 15min-UV-A irradiation excites higher ROS production than 5min-UV-A irradiation does in the ovarian cells, the maximum ROS content is about 7.1 times in Tn5B1-4 cells and 4.3 times in Sf-21 cells, and the maximum malondialdehyde levels in Tn5B1-4 and Sf-21 cells are about 1.47- and 1.36-fold higher than the control groups, respectively. Oxidative stress generated by PAT strongly decreases the activities of POD, SOD and CAT, and induces an accumulation of Tn5B1-4 cells in S phase and Sf-21 cells in G2/M phase in a concentration-dependent fashion. Apoptosis accumulation of Tn5B1-4 cells and the persistent post-irradiation cytotoxicity are further observed, indicating different antioxidative tolerance and arrest pattern of the two ovarian cells towards the cytotoxicity of PAT.

Effect and interaction study of acetamiprid photodegradation using experimental design.

The methodology of experimental research was carried out using the MODDE 6.0 software to study the acetamiprid photodegradation depending on the operating parameters, such as the initial concentration of acetamiprid, concentration and type of the used catalyst and the initial pH of the medium. The results showed the importance of the pollutant concentration effect on the acetamiprid degradation rate. On the other hand, the amount and type of the used catalyst have a considerable influence on the elimination kinetics of this pollutant. The degradation of acetamiprid as an environmental pesticide pollutant via UV irradiation in the presence of titanium dioxide was assessed and optimized using response surface methodology with a D-optimal design. The acetamiprid degradation ratio was found to be sensitive to the different studied factors. The maximum value of discoloration under the optimum operating conditions was determined to be 99% after 300 min of UV irradiation.

Investigating Role of Abiotic Factors on Spinosad Dissipation.

The effect of abiotic factors on dissipation of spinosad (soil moisture regimes, pH, and light) was studied. Spinosad residues were estimated using high performance liquid chromatography fitted with a UV detector. Under laboratory conditions, half-lives of spinosad were 9.0 and 7.7 days for air dried and field capacity soils, respectively. Percent dissipation of spinosad after 30 days was 47.02, 22.35, 62.5, 68.23 and 76.47 in solution with an aqueous pH of 10.85, 9.15, 6.97, 3.90 and 2.04, respectively. The half-life of spinosad in UV and sunlight was only 1.6 and 5.2 h, respectively. Light, especially the UV component, is an important factor for degradation of spinosad compared to other abiotic conditions.

Photodegradation of neonicotinoid insecticides in water by semiconductor oxides.

The photocatalytic degradation of three neonicotinoid insecticides (NIs), thiamethoxam (TH), imidacloprid (IM) and acetamiprid (AC), in pure water has been studied using zinc oxide (ZnO) and titanium dioxide (TiO2) as photocatalysts under natural sunlight and artificial light irradiation. Photocatalytic experiments showed that the addition of these chalcogenide oxides in tandem with the electron acceptor (Na2S2O8) strongly enhances the degradation rate of these compounds in comparison with those carried out with ZnO and TiO2 alone and photolytic tests. Comparison of catalysts showed that ZnO is the most efficient for the removal of such insecticides in optimal conditions and at constant volumetric rate of photon absorption. Thus, the complete disappearance of all the studied compounds was achieved after 10 and 30 min of artificial light irradiation, in the ZnO/Na2S2O8 and TiO2/Na2S2O8 systems, respectively. The highest degradation rate was noticed for IM, while the lowest rate constant was obtained for AC under artificial light irradiation. In addition, solar irradiation was more efficient compared to artificial light for the removal of these insecticides from water. The main photocatalytic intermediates detected during the degradation of NIs were identified.

Enhanced Ga2O3-photocatalyzed and photochemical degradation of the Fipronil insecticide by UVC irradiation in mixed aqueous/organic media under an inert atmosphere.

Agrochemicals such as the insecticide Fipronil that bear fluoro groups are generally fat-soluble and nearly insoluble in water, so that their photodegradation in a heterogeneous aqueous gallium oxide dispersion presents some challenges. This article examined the photodegradation of this insecticide by solubilizing it through the addition of organic solvents (EtOH, MeOH, THF, 1,4-dioxane and ethylene glycol) to an aqueous medium and then subjecting the insecticide to 254 nm UVC radiation under photocatalytically inert (Ga2O3/N2) and air-equilibrated (Ga2O3/O2) conditions, as well as photochemically in the absence of Ga2O3 but also under inert and air-equilibrated conditions. Defluorination, dechlorination, desulfonation and denitridation of Fipronil were examined in mixed aqueous/organic media (10, 25 and 50 vol% in organic solvent). After 3 h of UVC irradiation (50 vol% mixed media) defluorination with Ga2O3/N2 was ∼65% greater than in aqueous media, and ca. 80% greater than the direct photolysis of Fipronil under inert (N2) conditions; under air-equilibrated conditions both Ga2O3-photocatalyzed and photochemical defluorination were significantly lower than in aqueous media. Dechlorination of Fipronil was ∼160% (Ga2O3/N2) and 140% (photochemically, N2) greater than in aqueous media; under air-equilibrated conditions, both photocatalyzed and photochemical formation of Cl(-) ions in mixed media fell rather short relative to aqueous media. The photocatalyzed (Ga2O3/N2) and photochemical (N2) conversion of the sulfur group in Fipronil to SO4(2(-)) ions was ca. 20% and 30% greater, respectively, in mixed media, while under air-equilibrated conditions photocatalyzed desulfonation was nearly twofold less than in the aqueous phase; direct photolysis showed little variations in mixed media. Denitridation of the nitrogens in Fipronil occurred mostly through the formation of ammonia (as NH4(+)) under all conditions with negligible quantities of NO3(-); again mixed media offered enhanced denitridation, particularly under inert N2 conditions. Time-of-flight electrospray (TOF-MS/ESI(-)) mass spectrometry revealed a fairly large number of intermediates formed in the degradation of Fipronil, particularly under photocatalytic conditions. Only a couple of intermediates were identified in the photodegradation and the presence of Ga2O3 enhanced the complexity of an already cumbersome problem owing to the involvement of organic solvents.

Maintenance of residual activity of Bt toxin by using natural and synthetic dyes: a novel approach for sustainable mosquito vector control.

Mosquito control protein from Bacillus thuringiensis gets inactivated with exposure to sunlight. To address this issue, the potential of synthetic and natural dye was investigated as sunlight protectants. Bt SV2 in absence of dyes when exposed to sunlight showed reduced effectiveness against the fourth instars of mosquito larvae. Whereas acriflavin, congo red and violacein were able to maintain 86.4%, 91.6% and 82.2% mosquito larvicidal efficacy of Bt SV2 against IVth instars larvae of Anopheles stephensi Meigen after exposure to sunlight. Similarly, beetroot dye, acriflavin, congo red and violacein maintained 98.4%, 97.1%, 90.8% and 70.7% larvicidal activities against Aedes aegypti Linnaeus after sunlight exposure. Prodigiosin was found to be the best photo-protectant by simultaneously protecting and enhancing Bt activity by 6.16% and 22.16% against A. stephensi and A. aegypti, respectively. Combination of dyes with Bt formulations can be a good strategy for mosquito control programmes in tropical and sub-tropical regions.

Degradation of imidacloprid containing wastewaters using ultrasound based treatment strategies.

The present work deals with application of sonochemical reactors for the treatment of imidacloprid containing wastewaters either individually or in combination with other advanced oxidation processes. Experiments have been performed using two different configurations of sonochemical reactors viz. ultrasonic horn (20 kHz frequency and rated power of 240 W) and ultrasonic bath equipped with radially vibrating horn (25 kHz frequency and 1 kW rated power). The work also investigates the effect of addition of process intensifying agents such as H2O2 and CuO, which can enhance the production of free radicals in the system. The combination studies with advanced oxidation process involve the advanced Fenton process and combination of ultrasound with UV based oxidation. The extent of degradation obtained using combination of US and H2O2 at optimum loading of H2O2 was found to be 92.7% whereas 96.5% degradation of imidacloprid was achieved using the combination of US and advanced Fenton process. The process involving the combination of US, UV and H2O2 was found to be the best treatment approach where complete degradation of imidacloprid was obtained with 79% TOC removal. It has been established that the use of cavitation in combination with different oxidation processes can be effectively used for the treatment of imidacloprid containing wastewater.

Degradation of imidacloprid using combined advanced oxidation processes based on hydrodynamic cavitation.

The harmful effects of wastewaters containing pesticides or insecticides on human and aquatic life impart the need of effectively treating the wastewater streams containing these contaminants. In the present work, hydrodynamic cavitation reactors have been applied for the degradation of imidacloprid with process intensification studies based on different additives and combination with other similar processes. Effect of different operating parameters viz. concentration (20-60 ppm), pressure (1-8 bar), temperature (34 °C, 39 °C and 42 °C) and initial pH (2.5-8.3) has been investigated initially using orifice plate as cavitating device. It has been observed that 23.85% degradation of imidacloprid is obtained at optimized set of operating parameters. The efficacy of different process intensifying approaches based on the use of hydrogen peroxide (20-80 ppm), Fenton's reagent (H2O2:FeSO4 ratio as 1:1, 1:2, 2:1, 2:2, 4:1 and 4:2), advanced Fenton process (H2O2:Iron Powder ratio as 1:1, 2:1 and 4:1) and combination of Na2S2O8 and FeSO4 (FeSO4:Na2S2O8 ratio as 1:1, 1:2, 1:3 and 1:4) on the extent of degradation has been investigated. It was observed that near complete degradation of imidacloprid was achieved in all the cases at optimized values of process intensifying parameters. The time required for complete degradation of imidacloprid for approach based on hydrogen peroxide was 120 min where as for the Fenton and advance Fenton process, the required time was only 60 min. To check the effectiveness of hydrodynamic cavitation with different cavitating devices, few experiments were also performed with the help of slit venturi as a cavitating device at already optimized values of parameters. The present work has conclusively established that combined processes based on hydrodynamic cavitation can be effectively used for complete degradation of imidacloprid.

Degradation of the pesticide carbofuran on clay and soil surfaces upon sunlight exposure.

In the present study, the photolysis of carbofuran has been undertaken under sunlight conditions and at the surface of model supports such as clay films and different soils collected from two different sites in Morocco (Tirs and Dahs). In all conditions, an efficient degradation occurred owing to direct light absorption and also to photoinduced processes involving either clays or natural organic matter moities. On kaolin films, the photodegradation kinetics appears to follow a first-order process that clearly depends on the film thickness. The diffusion of carbofuran from the lower part to the illuminated surface was found to be negligible when compared to the photolysis process within the range of 20-70 µm. Thus, the photolysis rate constant at the surface of the solid support, k (0), was evaluated to be 7.0 × 10(-3) min(-1). Under these experimental conditions, the quantum yield was found equal to 2.1 × 10(-4). On soil surfaces, the disappearance rate constant was mainly attributed to photoinduced processes arising from natural organic matter. From the analytical point of view, the products were formed through (1) hydroxylation on the aromatic ring, (2) homolytic scission of the carbamate C-O bond leading to radical species formation, and (3) photohydrolysis of the carbamate C-O bond.

Enhanced photoprotection for photo-labile compounds using double-layer coated corn oil-nanoemulsions with chitosan and lignosulfonate.

With the aim to establish a novel nanocarrier system with relatively high payload and high photoprotection capacity for photo-labile active compounds, in this work, deltamethrin (photo-labile compound) was encapsulated into corn oil-nanoemulsions (NE) by a hot high pressure homogenization technique followed by coating with chitosan as the first coating layer (CH-NE) and lignosulfonate as the second coating layer to form a double-layer coated NE (L-CH-NE). The optimal conditions for preparation of NE, chitosan coating and lignosulfonate coating were investigated. The results indicate that polymer coating and the number of coating layers significantly affected the release profile and photoprotection capacity of nanocarriers. In particular, after coating, the release rate became slower and photoprotection capacity became higher. Moreover, in the case of L-CH-NE after 24h of UV exposure in direct photolysis and 2.5h of UV exposure in indirect photolysis, the non-degraded amount of deltamethrin was approximately 4.5 times and 2.1 times, respectively, higher than that of the free-from deltamethrin. In the future, this novel nanocarrier system will show great potential and be widely applied to many fields related to protection of photo-labile compounds against photo-degradation.

Photocatalytic degradation with immobilised TiO(2) of three selected neonicotinoid insecticides: imidacloprid, thiamethoxam and clothianidin.

This research focused on photocatalytic degradation of imidacloprid, thiamethoxam and clothianidin employing a tailor-made photoreactor with six polychromatic fluorescent UVA (broad maximum at 355 nm) lamps and immobilised titanium dioxide (TiO(2)) on glass slides. The disappearance was followed by high pressure liquid chromatography (HPLC-DAD) analyses, wherein the efficiency of mineralization was monitored by measurements of total organic carbon (TOC). Within 2h of photocatalysis, all three neonicotinoids were degraded following first order kinetics with rate constants k=0.035 ± 0.001 min(-1) for imidacloprid, k=0.019 ± 0.001 min(-1) for thiamethoxam and k=0.021 ± 0.000 min(-1) for clothianidin. However, the rate of mineralization was low, i.e. 19.1 ± 0.2% for imidacloprid, 14.4 ± 2.9% for thiamethoxam and 14.1 ± 0.4% for clothianidin. This indicates that several transformation products were formed instead. Some of them were observed within HPLC-DAD analyses and structures were proposed according to the liquid chromatography-electro spray ionization tandem mass spectrometry analyses (LC-ESI-MS/MS). The formation of clothianidin, as thiamethoxam transformation product, was reported for the first time.

Degradation of dichlorvos using hydrodynamic cavitation based treatment strategies.

The degradation of an aqueous solution of dichlorvos, a commonly used pesticide in India, has been systematically investigated using hydrodynamic cavitation reactor. All the experiments have been carried out using a 20 ppm solution of commercially available dichlorvos. The effect of important operating parameters such as inlet pressure (over a range 3-6 bar), temperature (31 °C, 36 °C and 39 °C) and pH (natural pH = 5.7 and acidic pH = 3) on the extent of degradation has been investigated initially. It has been observed that an optimum value of pressure gives maximum degradation whereas low temperature and pH of 3 are favorable. Intensification studies have been carried out using different additives such as hydrogen peroxide, carbon tetrachloride, and Fenton's reagent. Use of hydrogen peroxide and carbon tetrachloride resulted in the enhancement of the extent of degradation at optimized conditions but significant enhancement was obtained with the combined use of hydrodynamic cavitation and Fenton's chemistry. The maximum extent of degradation as obtained by using a combination of hydrodynamic cavitation and Fenton's chemistry was 91.5% in 1h of treatment time. The present work has conclusively established that hydrodynamic cavitation in combination with Fenton's chemistry can be effectively used for the degradation of dichlorvos.

Photoelectrocatalytic degradation of high COD dipterex pesticide by using TiO2/Ni photo electrode.

A TiO2 thin film electrode deposited on porous nickel net (TiO2/Ni) was prepared by the sol-gel method, and the surface morphology, crystal structure features and the grain size were characterized by Field emission scan electron microscopy (FESEM) and X-ray diffraction (XRD). The photoelectrocatalytic system was set up using a UV high-pressure mercury lamp as the light source, TiO2 coated on foamed nickel as photo anode, Pt sheet as counter electrode and the pesticide dipterex in synthetic wastewater. Various factors that influence the photoelectrocatalytic decomposition of dipterex pesticide have been studied, such as degradation time, the type of electrolyte, current density, original pH value and different degradation methods. The prepared catalysts were employed to photoelectrocatalytically degrade the pesticide dipterex under UV irradiation, comparing the results with photocatalytic degradation and electrochemical oxidation. The results indicated that under the optimal conditions of 0.02 mol/L NaCl as the supporting electrolyte, current density = 2.5 mA/cm2, pH 6.0 and dipterex pesticide 40 mg/L, and reaction time 2 hr, dipterex chemical oxygen demand (COD) removal rate and organophosphorous conversion of up to 82.6% and 83.5% were achieved, respectively. The method of photoelectrocatalytic degradation is more efficient than photocatalysis and electrochemical oxidation. The possible roles of the electrolytes on the reactions and probable mechanisms were also discussed.

Effect of light and pH on persistence of flubendiamide.

Persistence of flubendiamide in soil as affected by UV and sunlight exposure and in water as affected by pH was studied. At field capacity moisture regime, soil was treated with flubendiamide and exposed to UV and sunlight. Dissipation for the pesticide followed mono-phasic first order kinetics. Residues of flubendiamide, as thin film on petri-plates and soil thin film, dissipated with half-lives of 7.0 and 9.1 days under UV light and 12.0 and 19.1 days under sunlight, respectively. Residues of flubendiamide dissipated faster under UV light as compared to sunlight. Persistence study in aqueous medium under different pH condition indicated that flubendiamide residues persisted in water beyond 250 days with half-lives ranging from 250.8 to 301.0 days. Dissipation in water was faster at pH 4.0 (T(1/2) 250.8 days), followed by pH 9.2 (T(1/2) 273.6 days) and 7.0 (T(1/2) 301.0 days).

Novel photodegradable insecticide W/TiO(2)/Avermectin nanocomposites obtained by polyelectrolytes assembly.

Stable and even microcrystals of Avermectin (AVM) were produced by recrystallization in presence of a stabilizer. Sequential layer growth was achieved by the layer-by-layer (LbL) self-assembly of biocompatible polyelectrolytes (PEs). The coated colloids were characterized using confocal laser scanning microscopy (CLSM) and scanning electron microscopy (SEM). The in vitro release of Avermectin from microcapsules was studied under the simulated insect midgut conditions. W-doped TiO(2) photocatalysts were synthesized by a simple hydrothermal method, and characterized by Brunauer-Emmett-Teller (BET) surface area measurements and SEM. The photocatalytic activities of photocatalysts, which were undoped with TiO(2) and W-doped TiO(2), were evaluated by the photocatalytic oxidation degradation of AVM microcapsules in aqueous solution under UV illumination. The toxicity of the photodegradable insecticide was evaluated by the adult stage Martianus dermestoides. The results showed that AVM microcrystals which were obtained by association had a mean length of 13.8µm and a zeta potential of -34.7mV. The drug loading and encapsulation efficiency were 65.57±0.96% and 46.15±0.96%, respectively. The in vitro release experiments revealed that the polyelectrolytes prolonged the release time of the encapsulated AVM microcrystals. The sample which was prepared at 120°C with 4.0mol% W-doped amount had the highest photocatalytic activity. Toxicity of the novel photodegradable insecticide was higher in the adult stage compared to the 95% AVM as indicated by the lower LC(50) value.

Sonophotocatalytic degradation of monocrotophos using TiO2 and Fe3+.

Monocrotophos (MCP) is an organophosphate insecticide that has been found as a pollutant in aqueous environments. The sonolytic, photocatalytic and sonophotocatalytic degradation of MCP in the presence of homogeneous (Fe(3+)) and heterogeneous photocatalysts (TiO(2)) were studied. The photocatalytic degradation rate using TiO(2) was found to be lower than that of sonolysis alone due to the interference of phosphate ions formed as an intermediate product. On the other hand, a 15 fold enhancement in the degradation rate was found when photolysis was carried out in the presence of Fe(3+) compared to the rate observed with photolysis alone. The combination of sonolysis and photocatalysis (using either TiO(2) or Fe(3+)) showed a detrimental effect. Synergy indices of 0.62 and 0.87 were found for the sonophotocatalytic degradation of MCP in the presence of TiO(2) and Fe(3+), respectively. Total organic carbon (TOC) analysis was carried out to study the extent of mineralization of MCP. It was found that the mineralization process was additive for both TiO(2) and Fe(3+) sonophotocatalysis. HPLC and electrospray mass spectrometry (ESMS) techniques were employed for the identification of the degradation intermediates. The sonication of MCP led to the formation of dimethyl phosphate, dimethylphosphonate, 3-hydroxy 2-buteneamide and N-methyl 3-oxobutanamide as the intermediate products.