Skip to main content

Degradation of paraquat herbicide using hybrid AOP process: statistical optimization, kinetic study, and estimation of electrical energy consumption



This work studied the performance of UV/PS/TiO2NPs and UV/PI/TiO2NPs as hybrid advanced oxidation processes for degradation of paraquat in aqueous solution, because this very toxic herbicide is used third most widely.


The effects of several factors such as UV irradiation, initial oxidant concentration, TiO2 nanoparticles dosage, and pH on the degradation efficiency were investigated. The process optimization was performed by the central composite design as a tool of response surface methodology for 30 mgL−1 of the herbicide initial concentration at 25 ℃ and 40 min of degradation process. Based on the results, a degradation efficiency of 77% and 90% were obtained for the UV/PS/TiO2NPs and UV/PI/TiO2NPs processes, respectively, in the optimum conditions. The mineralization efficiency of the paraquat solution using UV/PS/TiO2NPs and UV/PI/TiO2NPs processes are about 32% and 55%, respectively, after 40 min. The kinetic studies show that both processes follow a pseudo-first-order kinetic model, and the kinetic constants are 0.0299 min−1 for the PS process and 0.0604 min−1 for the PI process. The electrical energy consumption was estimated to be about 481.60 kWhm−3 for the PS process and 238.41 kWhm−3 for the PI process.


The degradation and mineralization efficiency of the paraquat solution using the UV/PI/TiO2NPs process was more than that of the UV/PS/TiO2NPs process at the optimum conditions after 40 min.


Paraquat (PQ) is a non-selective contact herbicide used to control or suppress a broad spectrum of emerged weeds. It is the most toxic herbicide, and the third most widely used in the world [1]. The United States Environmental Protection Agency (USEPA) has classified paraquat dichloride as a restricted-use pesticide due to its highly acute toxicity to animals and people from intentional or inadvertent exposure with acute oral toxicity of 4,4-bipyridyl with an LD50 value of 40–200 mg/kg of body weight. It has life-threatening effects on the gastrointestinal tract, kidneys, liver, heart, and other organs [2, 3].

In the recent years, advanced oxidation processes (AOPs) have been intensively studied as the most environmentally friendly and promising techniques for the degradation of recalcitrant organic pollutants in water by powerful oxidants, especially hydroxyl radicals and superoxide radicals [4,5,6,7,8,9,10].

Heterogeneous photocatalytic degradation in the presence of the nanostructure catalysts has attained good efficiencies in the degradation of organic compounds among the various AOPs [11,12,13,14,15,16,17,18]. In the photocatalytic activity process, the photoelectrons in the conduction band and highly oxidative holes in the valence band are produced, where a reaction occurs with the adsorbed water to form the highly reactive hydroxyl radicals according to Eqs. 18 [19].

$${\text{TiO}}_{{2}} \mathop{\longrightarrow}\limits^{{{\text{uv}}}}{\text{e}}_{{}}^{ - } + {\text{h}}_{{}}^{ + } ,$$
$${\text{TiO}_2}({{\text{h}}^ +)} + {{\text{H}}_2}{\text{O}_{\text{ad}}} \to {\text{TiO}_2} + {\text{HO}}\cdot + {{\text{H}}^+}$$
$${\text{Ti}}{{\text{O}}_{\text{2}}}{\text{(}}{{\text{e}}^{\text{ - }}}{\text{)}} + {{\text{O}}_{\text{2}}} \to {\text{Ti}}{{\text{O}}_{\text{2}}} + {\text{O}}_{\text{2}}^{\cdot{\text{ - }}},$$
$${\text{O}}_{\text{2}}^{ \cdot {\text{ - }}} + {{\text{H}}^ + } \to {\text{HO}}_{\text{2}}^ \cdot,$$
$${\text{O}}_{\text{2}}^{ \cdot {\text{ - }}} + 3{\text{HO}}_{\text{2}}^ \cdot \to {\text{H}}{{\text{O}}^ \cdot } + {\text{3}}{{\text{O}}_{\text{2}}} + {{\text{H}}_{\text{2}}}{\text{O}} + {{\text{e}}^ - }$$
$${\text{2HO}}_{\text{2}}^ \cdot \to {{\text{O}}_{\text{2}}} + {{\text{H}}_{\text{2}}}{{\text{O}}_{\text{2}}}$$
$${\text{H}}_{{2}} {\text{O}}_{{2}} + {\text{TiO}}_{{2}} {\text{(e}}^{ - } {)} \to {\text{TiO}}_{{2}} + {\text{HO}}^{ - } + {\text{HO}} ,$$
$${\text{H}}{{\text{O}}^ \cdot } + {\text{Organics}} \to {\text{Intermediates}} \to ... \to {\text{C}}{{\text{O}}_{\text{2}}} + {{\text{H}}_{\text{2}}}{\text{O}}$$

As another powerful AOP method, inorganic oxidants such as \({\text{ClO}}_{3}^{-},\) \({\text{BrO}}_{3}^{-},\) \({\text{H}}_{2}{\text{O}}_{2},\) \({\text{S}}_{2}{\text{O}}_{8}^{2-},\) and \({\text{IO}}_{4}^{-}\) are used for the removal and mineralization of various organic pollutants from aqueous solutions. They produce different highly reactive radicals and in the hybridizing oxidation processes they have synergistic effect which gives better results in comparison to the individual processes [20,21,22,23,24]. They have enhanced the rate of UV-induced decomposition of organic pollutants in the presence of photocatalysis. This enhancement is as a result of the reduction of electron/hole recombination because of the reaction of activated electron by active oxidant such as \({\text{S}}_{2}{\text{O}}_{8}^{2-}\) and \({\text{IO}}_{4}^{-}\) [25,26,27].

Undergoing photolysis or thermolysis in an aqueous solution, persulfate (PS) is decomposed to generate the reactive radicals (Eqs. 911) [28, 29].

$${\text{S}}_{2} {\text{O}}_{8}^{2 - } + {\text{UV }}\left( { < 270{\text{ nm}}} \right) \to 2{\text{SO}}_{4}^{ - } ,$$
$${\text{SO}}_{4}^{ - } + {\text{ H}}_{2} {\text{O }} \to {\text{SO}}_{4}^{2 - } + {\text{HO}}^{ \cdot } + {\text{ H}}^{ + } { }\left( {\text{at all pHs}} \right),$$
$${\text{SO}}_{4}^{ - } + {\text{ OH}}^{ - } { } \to {\text{SO}}_{4}^{2 - } + {\text{HO}}^{ \cdot } { }\left( {\text{at all pHs}} \right).$$

Periodate (PI), as an inorganic oxidant, can oxidize a wide range of organic compounds quickly due to the generation of highly reactive radicals and non-radical intermediates under photolysis in an aqueous solution (Eqs. 1219) [28,29,30].

$${\text{IO}}_4^ - + {\text{hv~}} \to {\text{IO}}_3^ \cdot + {{\text{O}}^{ \cdot - }} ,$$
$${{\text{O}}^{ \cdot - }} + {{\text{H}}^ + }\rightleftarrows {\text{O}}{{\text{H}}^ \cdot } ,$$
$${\text{O}}{{\text{H}}^ \cdot } + {\text{IO}}_4^ - \to {\text{O}}{{\text{H}}^ - } + {\text{IO}}_4^ \cdot ,$$
$$2{\text{O}}{{\text{H}}^ \cdot } \to {{\text{H}}_{\text{2}}}{{\text{O}}_{\text{2}}},$$
$$2{\text{IO}}_{4}^{ \cdot } { } \rightleftarrows {\text{ I}}_{2} {\text{O}}_{8},$$
$${\text{I}}_{2} {\text{O}}_{8} + {\text{ H}}_{2} {\text{O }} \to {\text{IO}}_{3}^{ - } + {\text{ IO}}_{4}^{ - } + 2{\text{H}}^{ + } + {\text{ O}}_{2},$$
$$2{\text{IO}}_{3}^{ \cdot } { } \rightleftarrows {\text{ I}}_{2} {\text{O}}_{6} ,$$
$${\text{I}}_{2} {\text{O}}_{6} + {\text{ H}}_{2} {\text{O }} \to {\text{IO}}_{3}^{ - } + {\text{IO}}_{4}^{ - } + 2{\text{H}}^{ + } .$$

AOPs have limitations. In general, one of the main limitations of AOPs is that they cannot be used for effluents with high pollutant content due to their high cost. Also, in the AOP methods, the safety aspects of using UV light should be considered in the design of the process and the relevant reactors, which is one of the limitations of process operating. Cantavenera et al. [31] investigated the photocatalytic degradation of PQ in the presence of polycrystalline TiO2 Degussa P25 irradiated by near-UV light. They observed an increase of both degradation and mineralization rates after an induction time of 45–60 min and the complete photocatalytic mineralization of PQ (20 mgL−1) after 3 h of irradiation using 0.4 g l−1 of catalyst at natural pH [31] such that both time and catalyst amount used were high. Ignace et al. [32] studied the photocatalytic degradation of PQ in a fixed bed photoreactor under UV irradiation at 368 nm. This contained ß-SiC alveolar foams coated with TiO2 P25. The results showed that under optimal operating conditions at natural pH = 6.7, [PQ] = 10 mgL−1), and flow (26 mL/min), degradation and mineralization obtained about 43% and 27% respectively, after about 70 min [32] and these results are low. Zahedi et al. [33] studied the photocatalytic degradation of paraquat herbicide in the presence TiO2 nanostructure thin films under visible and sunlight irradiation using continuous flow photoreactor. The results indicated that at optimum pH 5.8, maximum decomposition of 84.39% in 5 h occurred under visible irradiation with initial concentration of 10 mgL−1 and the amount of photocatalyst of 30.8 g [33] such that both time and used catalyst amount were high.

The aim of this work is comparative study of the performance of UV/PS/TiO2NPs and UV/PI/TiO2NPs as hybrid AOPs and synergistic effect of these hybrid processes for degradation of the paraquat herbicide in aqueous solution. The process was modeled and optimized by response surface methodology (RSM). Also, the kinetic and the electrical energy consumption were assessed. So far, researchers have not studied the electrical energy consumption for the hybrid photocatalytic/periodate and persulfate process of paraquat herbicide and, this assessment have been performed in this work for the first time.


Materials and instruments

A standard solution of PQ (42%) with the chemical name of 1,1dimethyl-4,4-bipyridinium dichloride, whose molecular structure is shown in the Additional file 1: Figure S1, was prepared from the Golsam Chemicals Company. Anatase TiO2 nanopowder (purity: > 99%, APS: 10–25 nm, SSA: 200–240 m2g−1, color: white) was supplied from the US Research Company as a photocatalyst; its TEM and XRD analysis results are shown in Additional file 1: Figs. S2 and S3. Sodium periodate and sodium persulfate were used as the oxidants. Hydrochloric acid (2N) and sodium hydroxide (2N) were used to adjust the solution pH, and in all the experiments, deionized water was utilized to prepare the solutions. All the chemicals used were Merck and Fluka products.

The concentration of PQ was measured by a UV–visible spectrophotometer (Double-beam Rally UV-2601). The total organic carbon (TOC) analysis was carried out using a multi-N/C 3100 (Germany) instrument.

Photochemical reactor

A UVC lamp (Philips, 150 W and λmax = 254 nm) was used as the light source fixed into the quartz tube and located in the center of the reactor. A cylindrical Pyrex container with a volume of 500 mL, which was equipped with a cooling jacket to control the temperature, was used as the reactor vessel. The reactor content was stirred by a magnetic stirrer. A schematic representation of the photoreactor is shown in Fig. 1.

Fig. 1
figure 1

Schematic representation of the photoreactor 1, magnetic stirrer 2, reactor vessel 3, UV lamp and its quartz cover


In each run of the process, 400 mL of the PQ solution with the desired initial concentration and pH value was transferred into the reactor. A certain amount of the TiO2 nanopowder and the inorganic oxidant was added, and after mixing well the UV lamp was switched on to initiate the process. At regular time intervals, the samples were withdrawn, and the degradation studies were carried out by measuring the absorbance at λmax = 258 nm that corresponded to C=C bands in the pyridinium ring with the help of a UV–visible spectrophotometer (Fig. 2) [34]. Also the mineralization study was carried out by measuring the TOC of the samples (Additional file 1: Fig. S5).

Fig. 2
figure 2

UV spectrum of [PQ] (3 mgL−1 in pH = 6.5)

The percentages of degradation and mineralization were calculated according to the following equations:

$$\% {\text{ Degradation}} = \frac{{C_{0} - C_{i}}}{C_{0}} \times 100,$$

where C0 and Ci are the concentrations of PQ before and after treatment.

$$\%{\text{ Mineralization }} = \frac{{ {\rm TOC}_{\rm initial} - {\rm TOC}_{t} }}{{{\rm TOC}_{\rm initial}}} \times 100 \%,$$

where TOCt is the TOC at time ‘t’ [34].

Design of experiments

The effects of various experimental parameters on the efficiency of the degradation processes and their optimum values were studied using the central composite design (CCD) as one of the important tools of the RSM [35]. RSM is one of the useful mathematical and statistical methods for analyzing the relation between several independent variables [36].

CCD was used to optimize the values of the significant variables and obtain the best quantitative response. Also, it reduced the effects of the uncontrolled variables [37].

The total number of experiments (N) could be determined as follows [38, 39]:

$$N = 2^{k} + 2k + N_{0} ,$$

where k, 2 k, 2 k, and N0 are the number of factors, the terms of cubic points, the axial points, and the center points, respectively.

Thus CCD is able to model and optimize the related operational factors of AOPs and can specify the possible interaction between them [38].

In this work, the three important factors initial pH, TiO2NPs dosage, and inorganic oxidant concentration were optimized based on the obtained degradation efficiency (DE) of PQ as the response via the CCD method.


Experimental design

To design the experiments, the effective operational parameters such as the PS and PI concentrations, initial pH, and TiO2NPs dosage were considered to be optimized by the DOE software. Next, by introducing the parameters and their levels to the DOE software, 20 tests were designed to be done for both processes. The tests were performed, and their correlated DE was calculated and introduced to the software as a response. The range of the variables companion with the designed experiments for the UV/PS/TiO2NPs and UV/PI/TiO2NPs processes are shown in Tables 1 and 2, respectively.

Table 1 Range of the variables and the designed experiments as well as the corresponding responses for the PS process ([PQ] = 30 mgL−1, T = 25 °C)
Table 2 Range of the variables and the designed experiments as well as the corresponding responses for the PI process ([PQ] = 30 mgL−1, T = 25 °C)

After the regression analysis of the data, a second-order polynomial equation was suggested by the software to predict the response of the processes of UV/PS/TiO2NPs and UV/PI/TiO2NPs.

The significance of the model and its terms was evaluated by the analysis of variance (ANOVA) such that the p values less than 0.05 and greater than 0.10 indicated that the model terms were significant and not significant, respectively. The terms TiO2NPs, pH2, PS, and \({\text{PS}} \times {\text{pH}}\) in the PS process, and the terms PI2, pH2, and TiO2NPs in the PI process were significant. The ANOVA output for the reduced quadratic models (Eqs. 23 and 24) is demonstrated in Tables 3 and 4 for the UV/PS/TiO2NPs and UV/PI/TiO2NPs processes, respectively. The model F value of 110.37 and the p value < 0.0001 for the UV/PS/TiO2NPs process, and the F value of 41.12 and the p value < 0.0001 for the UV/PI/TiO2NPs process imply that the models are significant.

Table 3 ANOVA for the response surface reduced quadratic model for the PS process
Table 4 ANOVA for the response surface reduced quadratic model for the PI process
$$\%\text{DE}=9.01321+0.13468\text{ PS}+4.99923\text{ pH}+0.02698\text{ Ti}{\text{O}}_{2}\text{NPs}-0.00459\text{ PS }\times \text{pH}-0.25118\text{ p}{\text{H}}^{2},$$
$$\text{\%DE}=-64.83410+1.08949\text{ PI}+20.05376\text{ pH}+0.12196\text{ Ti}{\text{O}}_{2}\text{NPs}-0.00434\text{ P}{\text{I}}^{2}-1.35832\text{p}{\text{H}}^{2}.$$

The "Pred R-Squared" of 0.93 and "Adj R-Squared" of 0.97 represent that the model predicts the response as well, and the "Adeq Precision" of 38.26 indicates an adequate signal-to-noise ratio (a ratio greater than 4 is desirable). The R2 of 0.97 implies that the model can predict the UV/PS/TiO2NPs process performance. Also in the case of the UV/PI/TiO2NPs process, the "Pred R-Squared", "Adj R-Squared", and “Adeq Precision” were 0.78, 0.91, and 19.73, respectively. The R2 of 0.94 implies that the model can predict the UV/PI/TiO2NPs process performance. The adequacy of the models was graphically evaluated and approved by the diagnostic plots (Additional file 1: Fig. S6a, b).


The effects of the operational factors on the process were assessed by the 3D surface graphs. Figures 3 and 4 show the variation in the degradation efficiency as a function of the initial pH, the dose of TiO2NPs, and the oxidant dosage (PS and PI), while the PQ initial concentration is 30 mgL−1 in all tests. Figure 3 shows that the efficiency of the PI process at the neutral condition is more than that for the alkaline and acidic conditions, and it decreases intensity at the acidic condition, while the activity of PS is independent of the pH variations. Figure 4 shows that the degradation efficiency is increased by increasing the PI, PS, and TiO2NPs concentrations for both processes at a constant pH. This increase is very intensive for PI due to the production of more radicals (Eqs. 1219). Thus PI is a stronger and more active oxidizer.

Fig. 3
figure 3

Response surface graphs of the variation in DE versus (a) the initial pH and the PS amount (mg L−1), b the initial pH and the PI amount (mg L−1) ([PQ] = 30 mgL−1 and T = 25 °C)

Fig. 4
figure 4

Response surface graphs for variation DE versus (a) the initial TiO2NPs and the PS amount, b the initial TiO2NPs and the PI amount ([PQ] = 30 mgL−1 and T = 25 °C)

The operational parameters were numerically optimized based on the models (Eqs. 23 and 24) using the related numerical facilities of the applied software. For this aim, the goals of the three variables and the model response were set at “in the range” and “maximizing”, respectively. The desirability ramps for the numerical optimization of the UV/PS/TiO2 NPs and UV/PI/TiO2 NPs processes are shown in the Additional file 1: Figs. S7 and S8. For the PS process, in the optimum conditions of [PS] = 400 mgL−1, [TiO2NPs] = 150 mgL−1, and [pH]in = 6.3, the predicted DE is about 77%. Also DE for the PI process is about 90% in the optimum conditions of [PI] = 90 mgL−1, [TiO2NPs] = 125 mgL−1, and [pH]in = 6. To assess the accuracy of the model prediction, under the supposed values of the parameters, the photocatalytic degradation efficiency empirically reached 90% (i.e., 0% error) for the PI process and 83% (i.e., 6% error) for the PS process. Comparison of the several studies on degradation of paraquat by AOPs is presented in Table 5. Considering the table, it can be concluded that UV/PI/TiO2NPs and UV/PS/TiO2NPs processes (this study) have a good ability to remove paraquat, rather than other studies.

Table 5 Comparison of the several studies’ results on degradation and mineralization of PQ by AOPs

The degradation kinetic of PQ was assessed under the optimum conditions for both processes based on pseudo-first-order equation as follows:

$$\ln \frac{{PQ_{0} }}{{PQ_{t} }} = kt ,$$

where [PQ]0, [PQ]t, k, and t are the initial and at any time concentrations of the PQ, first-order kinetic constant, and process time, respectively.

The linear relationship between the investigated results for both the PS and PI processes shows that they follow the first-order kinetics; the fitting is shown in Fig. 5. Plotting the variation in the logarithmic concentration ratio versus the irradiation time forms a straight line with a slope equal to kapp. The kinetic constant was 0.0299 min−1.

Fig. 5
figure 5

Linear fittings of the first-order kinetic model for the PQ degradation (PQ = 30 mg L−1 and T = 25 °C), using (a) PS process and b PI process

Mineralization is the process of complete oxidative degradation of an organic compound and the relevant intermediates to CO2, H2O, and other mineral oxides [25, 42]. For detection of the degradation of PQ, the UV–visible spectrophotometry analysis is used, and to investigate the mineralization, the total organic carbon (TOC) test should be used. This test was performed on the PQ solution treated by the photocatalytic process under the optimum conditions. The TOC results showed that the photocatalytic processes of UV/PS/ TiO2NPs and UV/PI/TiO2NPs were able to mineralize the PQ solution about 32% and 55%, respectively, after 40 min. To confirm the ability of the process to remove more TOC, the process continued by adding 90 mgL−1 of periodate and 400 mgL−1 persulfate for up to 120 min, so that the amount of TOC removal reached to 64 and 82% for UV/PS/TiO2NPs and UV/PI/TiO2NPs, respectively.

The electrical energy consumption (EEC) is one of the important criteria in the photochemical process. The figure of merit is the electrical energy per order, defined as the number of KWh of electrical energy required for reducing the concentration of a pollutant by one order of magnitude (i.e., 90% degradation) in 1 m3 of contaminated water and can be calculated as follows [43]:

$${\text{EEC}} = \frac{{1000{\text{Pt}} }}{{60 \ V\,{\text{log}} \left( {\frac{ [PQ]_{0}}{[PQ ]}} \right)}},$$

where P is the electrical power (kW) of the light source in the photochemical system, V is the volume (L) of the treated solution, and t is the irradiation time (min). According to the first-order kinetic for the photocatalytic process, the constant ratio of log([PQ]0/[PQ])/t represents the rate constant, k (in unit of min−1), and therefore, Eq. 26 can be re-written as follows:

$${\rm EEC} = \frac{{38.4 \times P}}{{V \times k}}.$$

Hence, under the optimum conditions of the photocatalytic PS and PI processes and considering the rate constant of 0.0299 min−1 for the PS process and the rate constant of 0.0604 min−1 for the PI process, 150 W light source, and 0.4 L of treated PQ solution, EEC was calculated as 481.60 kWhm−3 for the PS process and 238.41 kWhm−3 for the PI process after 60 min.


In this work, a photocatalytic process was applied using the TiO2NPs, and the PS and PI oxidizers to degrade PQ as a highly toxic herbicide. The experiments were designed based on the CCD method, and also the processes were modeled. The operating parameters were optimized based on the models as follows: the initial pH = 6.3, [PS] = 400 mgL−1 and [TiO2NPs] = 150 mgL−1 for the PS process; and the initial pH = 6, [PI] = 90 mgL−1, and [TiO2NPs] = 125 mgL−1 for the PI process. Under the optimized conditions, the models predicted the efficiency of about 77% for the UV/PS/TiO2 process and 90% for the UV/PI/TiO2NPs process; they were confirmed empirically with only 6% and 0% errors, respectively. The photocatalytic PQ degradation for both processes was well fitted by a pseudo-first-order kinetic model with a rate constant of 0.0299 min−1 for the UV/PS/TiO2NPs process and a rate constant of 0.0604 min−1 for the UV/PI/TiO2NPs process. Under the optimum conditions, the PQ molecules were mineralized for about 32% and 55% after 40 min for the UV/PS/TiO2NPs and UV/PI/TiO2NPs processes, respectively. The electrical energy consumption for the performance of the photocatalytic process at the optimum conditions after 60 min were calculated as 481.60 kWhm−3 for the UV/PS/TiO2NPs process and 238.41 kWhm−3 for the UV/PI/TiO2NPs process. Based on the results obtained, PI is a stronger, more active, and economical oxidizer than PS. The main result of this work compared to other works is to achieve proper efficiency with less oxidant consumption.

Availability of data and materials

The datasets used and/or analyzed during the current study are available from the corresponding author on reasonable request.





Advanced oxidation processes


Nanoparticles of TiO2


Response surface methodology


Sodium periodate


Sodium persulfate


Total organic carbon


Central composite design


Degradation efficiency




Electrical energy consumption


  1. Bromilow RH (2004) Paraquat and sustainable agriculture. Pest manag sci 60:340–349

    Article  CAS  Google Scholar 

  2. Agency, U.S.E.P. (1997) Paraquat dichloride. In Reregistration Eligibility Decision (RED). Washington, D.C. p. 20460

  3. Watts M (2010) Paraquat. Pesticied Action Network Asia and the Pacific, Malaysia

    Google Scholar 

  4. Özkara A, Akyıl D, Konuk M, Pesticides (2016) Environmental pollution and health, (Environmental health risk—hazardous factors to living species)

  5. Chu W, Rao YF (2012) Photocatalytic oxidation of monuron in the suspension of WO3 under the irradiation of UV–visible light. Chemosphere 86:1079–1086

    Article  CAS  Google Scholar 

  6. Del Moro G, Mancini A, Mascolo G, Di Iaconi C (2013) Comparison of UV/H2O2 based AOP as an end treatment or integrated with biological degradation for treating landfill leachates. Chem Eng J 218:133–137

    Article  Google Scholar 

  7. Ameta SC, Ameta R (2018) Advanced Oxidation Processes for Wastewater Treatment. Emerging Green Chemical Technology, 1st edn, PAHER University, Elsevier, Environmental Science).

  8. Kumar MS, Sonawane SH, Pandit AB (2017) Degradation of methylene blue dye in aqueous solution using hydrodynamic cavitation based hybrid advanced oxidation processes. Chem Eng Process 122:288–295

    Article  CAS  Google Scholar 

  9. Goel M, Seepana M (2016) Photochemical removal of pesticides: a review mater. Sci Forum 855:127–138

    Article  Google Scholar 

  10. Miklos DB (2018) Evaluation of advanced oxidation processes for water and wastewater treatment—a critical review. Water Res 139:118–131

    Article  CAS  Google Scholar 

  11. Sillanpää M, Matilainen A (2010) Removal of natural organic matter from drinking water by advanced oxidation processes. Chemosphere 80:159–211

    Google Scholar 

  12. Znad H, Abbas K, h, Hena S, Awual MR, (2018) Synthesis a novel multilamellar mesoporous TiO2/ZSM-5 for photo-catalytic degradation of methyl orange dye in aqueous media. J Env Chem Eng 6:218–227

    Article  CAS  Google Scholar 

  13. Hodges BC, Cates EL, Kim JH (2018) Challenges and prospects of advanced oxidation water treatment processes using catalytic nanomaterials. Nature Nanotechnol 13(8):642–650

    Article  CAS  Google Scholar 

  14. Medynska AZ (2018) Photocatalysis in metal oxide-based photocatalysis: fundamentals and prospects for application. In: Korotcenkov G, ed; p. 279–282

  15. Moshe TB, Dror I, Berkowitz B (2009) Oxidation of organic pollutants in aqueous solutions by nanosized copper oxide catalysts. Appl Cata B Environ 85:207–211

    Article  Google Scholar 

  16. Atalay S, Ersöz G (2016) Review on catalysis in advanced oxidation processes in springer briefs in molecular science, novel catalysts in advanced oxidation of organic pollutants, p. 35–58

  17. Wang Y (2016) The application of nano-TiO2 photo semiconductors in agriculture. Nanoscale Res Lett 11:1–7

    Article  Google Scholar 

  18. Jain A, Vaya D (2017) Photocatalytic activity of TiO2 nanomaterial. J Chil Chem Soc 62:3683–3690

    Article  CAS  Google Scholar 

  19. Binas V (2017) Modified TiO2 based photocatalysts for improved air and health quality. J Materiomics 1:3–16

    Article  Google Scholar 

  20. Eskandarloo H, Badiei A, Behnajady MA (2015) Optimization of UV/inorganic oxidants system efficiency for photooxidative removal of an azo textile dye. Desalin Water Treat 1:210–226

    Article  Google Scholar 

  21. Wang Y, Hong CS (1999) Effect of hydrogen peroxide, periodate and persulfate on photocatalysis of 2-chlorobiphenyl in aqueous TiO2 suspensions. Water Res 9:2031–2036

    Article  Google Scholar 

  22. Elddine HAN (2015) Kinetic study of the discoloration of the food colorant E131 by K2S2O8 and KIO3. Port Electrochim Acta 5:275–288

    Article  Google Scholar 

  23. Jafarinejad S (2017) Cost-Effective catalytic materials for AOP treatment units in applications of advanced oxidation processes (AOPs) in drinking water treatment. Springer International Publishing AG, The Handbook of Environmental Chemistry, pp 309–343

    Book  Google Scholar 

  24. Ali R, Hassan SH (2008) Degradation studies on paraquat and malathion using TiO2 /ZnO based photocatalyst. Malaysian J Anal Sci 12:77–87

    Google Scholar 

  25. Saien J (2017) Photo-activated periodate in homogeneous degradation and mineralization of quinoline: optimization, kinetic, and energy consumption. Environ Prog Sustain Energy 36:1621–1627

    Article  CAS  Google Scholar 

  26. Sharma J, Mishra IM, Kumar V (2015) Degradation and mineralization of bisphenol A (BPA) in aqueous solution using advanced oxidation processes: UV/H2O2 and UV/S2O82- oxidation systems. J Environ Manage 156:266–275

    Article  CAS  Google Scholar 

  27. Sahoo MK (2013) Improving the operational parameters with high electrical energy efficiency for UVC induced advanced oxidation and mineralization of Acid blue 29: generation of eco-friendly effluent. Sep Purif Technol 106:110–116

    Article  CAS  Google Scholar 

  28. Cao MH (2010) Photochemical decomposition of perfluorooctanoic acid in aqueous periodate with VUV and UV light irradiation. J Hazard Mater 179:1143–1146

    Article  CAS  Google Scholar 

  29. Chia LH, Tang X, Weavers LK (2004) Kinetics and mechanism of photoactivated periodate reaction with Chlorophenol in acidic solution. Environ Sci Technol 38:6875

    Article  CAS  Google Scholar 

  30. Lia T (2016) Transformation of humic acid and halogenated byproduct formation in UV-chlorine processes. Water Res 102:421–427

    Article  Google Scholar 

  31. Cantavenera MJ (2007) Photocatalytic degradation of paraquat and genotoxicity of its intermediate products. J Photochem Photobiol A Chem 185:277–282

    Article  CAS  Google Scholar 

  32. Ignace CMB, Atheba GP, Didier R, Drogui P, Trokourey A (2019) Photocatalytic degradation of paraquat herbicide using a fixed bed reactor containing TiO2 nanoparticles coated onto ß-SiC alveolar foams. American J Ana Chem 10:171–184

    Article  Google Scholar 

  33. Zahedi F, Behpour M, Ghoreishi SM, Khalilian H (2015) Photocatalytic degradation of paraquat herbicide in the presence TiO2 nanostructure thin films under visible and sun light irradiation using continuous flow photoreactor. Sol Energy 120:287–295

    Article  CAS  Google Scholar 

  34. Sahoo MK (2012) UVC induced TOC removal studies of Ponceau S in the presence of oxidants: evaluation of electrical energy efficiency and assessment of biotoxicity of the treated solutions by Escherichia coli colony forming unit assay. Chem Eng J 213:142–149

    Article  CAS  Google Scholar 

  35. Montgomery DC (2009) Design and Analysis of Experiments, 9th edn. Wiley, Arizona State University

    Google Scholar 

  36. Beher SK (2018) Application of response surface methodology (RSM) for optimization of leaching parameters for ash reduction from low-grade coal. Int J Mining Sci Technol 28:621–629

    Article  Google Scholar 

  37. Vahidian HR, Zarei AR, Soleymani AR (2016) Degradation of nitro-aromatic explosives using recyclable magnetic photocatalyst: catalyst synthesis and process optimization. J Hazard Mater 325:310–318

    Article  Google Scholar 

  38. Martins LR (2017) Optimization of cellulose and sugarcane bagasse oxidation: application for adsorptive removal of crystal violet and auramine-O from aqueous solution. J Colloid Interf Sci 494:223–241

    Article  CAS  Google Scholar 

  39. Raissi S, Farsani RE (2009) Statistical process optimization through multi-response surface methodology. World Acad Sci Eng Technol 51:267

    Google Scholar 

  40. Dhaouadi A, Adhoum N (2010) Heterogeneous catalytic wet peroxide oxidation of paraquat in the presence of modified activated carbon. App Cata B Env 97:227–235

    Article  CAS  Google Scholar 

  41. Tantriratna P, Wirojanagud W, Neramittagapong S, Wantala K, Grisdanurak N (2011) Optimization for UV-photocatalytic degradation of paraquat over titanium dioxide supported on rice husk silica using Box-Behnken design. Indian J Chem Tech 8:363–371

    Google Scholar 

  42. Marien CBD (2016) TiO2 Nanotube arrays: influence of tube length on the photocatalytic degradation of Paraquat. Appl Catal B Environ 194:1–6

    Article  CAS  Google Scholar 

  43. Bolton JR (2001) Figures-of-merit for the technical development and application of advanced oxidation technologies for both electric-and solar-driven systems (IUPAC Technical Report), Pure Appl. Chem 73:627–637

    CAS  Google Scholar 

Download references


Not applicable.


There is no significant financial support for this work that could have influenced its outcome.

Author information

Authors and Affiliations



GB: supervision and finalization of the manuscript, HRV: advisor and design of experiments, AG: doing the experiment and writing the original draft of the manuscript. It is confirmed that the manuscript has been read and approved by all named authors and is confirmed that the order of authors listed in the manuscript has been approved by all of authors. All authors read and approved the final manuscript.

Corresponding author

Correspondence to Azam Ghavi.

Ethics declarations

Ethical approval and consent to participate

Not applicable.

Consent for publication

Not applicable.

Competing interests

The authors declare that there is no conflict of interest associated with this publication.

Additional information

Publisher's Note

Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.

Supplementary Information

Additional file 1.

Degradation of paraquat herbicide using hybrid AOP process: statistical optimization, kinetic study, and estimation of electrical energy consumption.

Rights and permissions

Open Access This article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons licence, and indicate if changes were made. The images or other third party material in this article are included in the article's Creative Commons licence, unless indicated otherwise in a credit line to the material. If material is not included in the article's Creative Commons licence and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this licence, visit

Reprints and permissions

About this article

Check for updates. Verify currency and authenticity via CrossMark

Cite this article

Ghavi, A., Bagherian, G. & Rezaei-Vahidian, H. Degradation of paraquat herbicide using hybrid AOP process: statistical optimization, kinetic study, and estimation of electrical energy consumption. Environ Sci Eur 33, 117 (2021).

Download citation

  • Received:

  • Accepted:

  • Published:

  • DOI: