Behnajady-Modirshahla-Ghanbery Research Articles

Phosphate Removal Efficiency and Life Cycle Assessment of Different Anode Materials in Electrocoagulation Treatment of Wastewater

The excessive discharge of phosphorus-containing wastewater contributes to eutrophication, posing a serious threat to aquatic ecosystems. Therefore, methods such as electrocoagulation should be utilized to remove phosphorus from wastewater prior to discharging it into a water body. In this study, we aimed to determine the effectiveness of electrocoagulation in treating simulated phosphorus-containing wastewater under different parameters, including anode material (aluminum, iron, and magnesium), electrode distance (ED) (1, 2.5, and 4.5 cm), pH (3, 6, and 9), and current density (CD) (3, 6, and 9 mA/cm2). Additionally, three models of phosphate removal, the pseudo-first-order (PFO), pseudo-second-order (PSO), and Behnajady–Modirshahla–Ghanbery (BMG) models, were used to simulate the relationship between phosphate concentration and time in the electrocoagulation process using the three metals for phosphate removal. The experimental results showed that the aluminum system had the highest removal efficiency (90%) when energized for 20 min under a CD of 3 mA/cm2, followed by those of the iron (80%) and magnesium (35%) systems. Furthermore, a life cycle assessment (LCA) showed that the aluminum electrode system had a smaller environmental impact than the iron and magnesium electrode systems. Therefore, the aluminum electrode system is suitable for phosphorus removal from wastewater.

RESPONSE SURFACE METHODOLOGY APPLIED TO ELECTRO-FENTON PROCESS FOR DEGRADATION OF RED BEMACID AS TEXTILE DYE MODEL

The textile industry produces persistent organic pollutants (POPs) that pose significant risks to ecosystems because of their toxic and hazardous nature. Consequently, there is an urgent requirement for the development of effective techniques to treat the effluents and remove these compounds. This work studied the viability of the Electro-Fenton (EF) process as a potential alternative for treating textile wastewater contaminated with POPs. A batch electrochemical reactor, equipped with a platinum grid cathode and stainless-steel sacrificial anode, was utilized to eliminate Red Bemacid (RB) dye. The study investigated the impact of four key operational parameters: (i) stirring speed (rpm), (ii) oxygen flow rate (L/min), (iii) supporting electrolyte concentration [Na2SO4] (mg/L), and (iv) current intensity (A), as well as their interactions on RB removal. To perform this, Central Composite Experimental Design (CCD) and Response Surface Methodology (RSM) were employed. Under optimized EF conditions for RB removal (stirring speed = 205.09 rpm, oxygen flow rate = 0.20 L/min, current intensity = 0.306 A, and supporting electrolyte concentration = 0.09 M), the EF process demonstrated exceptional removal efficiency, achieving approximately 94.51% removal of RB. The obtained results showed that the kinetic data of RB removal were in good agreement with the Behnajady-Modirshahla-Ghanbery (BMG) model. The CCD analysis revealed that the main effect of the current intensity had a significant impact on RB removal, as well as the interaction of all paired variables.

Effective Removal of Glyphosate from Aqueous Systems Using Synthesized PEG-Coated Calcium Peroxide Nanoparticles: Kinetics Study, H2O2 Release Performance and Degradation Pathways.

Glyphosate (N-phosphonomethyl glycine) is a non-selective, broad-spectrum organophosphate herbicide. Its omnipresent application with large quantity has made glyphosate as a problematic contaminant in water. Therefore, an effective technology is urgently required to remove glyphosate and its metabolites from water. In this study, calcium peroxide nanoparticles (nCPs) were functioned as an oxidant to produce sufficient hydroxyl free radicals (·OH) with the presence of Fe2+ as a catalyst using a Fenton-based system. The nCPs with small particle size (40.88 nm) and high surface area (28.09 m2/g) were successfully synthesized via a co-precipitation method. The synthesized nCPs were characterized using transform infrared spectroscopy (FTIR), X-ray diffractometry (XRD), Brunauer-Emmett-Teller analysis (BET), dynamic light scattering (DLS), and field emission scanning electron microscopy (FESEM) techniques. Under the given conditions (pH = 3.0, initial nCPs dosage = 0.2 g, Ca2+/Fe2+ molar ratio = 6, the initial glyphosate concentration = 50 mg/L, RT), 99.60% total phosphorus (TP) removal and 75.10% chemical oxygen demand (COD) removal were achieved within 75 min. The degradation process fitted with the Behnajady-Modirshahla-Ghanbery (BMG) kinetics model. The H2O2 release performance and proposed degradation pathways were also reported. The results demonstrated that calcium peroxide nanoparticles are an efficient oxidant for glyphosate removal from aqueous systems.

Optimization Method to Determine the Kinetic Rate Constants for the Removal of Benzo[a]pyrene and Anthracene in Water through the Fenton Process

The reaction rate constants concerning the removal of benzo[a]pyrene (BaP) and anthracene (AN) in water by the Fenton process can be commonly found from the experimental data and by using regression models. However, this calculation is a time-consuming and a difficult task. Therefore, an algorithm for the determination of the rate constants depletion of the pollutants of interest should be developed. In this study, several algorithms were developed, using MATLAB® software for representing AN and BaP elimination by the Fenton process under an experimental domain. These algorithms were derived from the first-, second- and third-order kinetic models, as well as from the double exponential and the Behnajady-Modirshahla-Ghanbery (BMG) kinetic models. Regarding the AN and BaP removal kinetics, the double exponential and the BMG models were found to exhibit the highest correlation coefficients (>0.98 and >0.95, respectively) in comparison with those ones obtained from the first-, second- and third-order kinetic models (>0.80, >0.85 and >0.88, respectively). It was found that the algorithms can be used to optimize and fit the rate constants by creating an objective function that fits and represents the experimental data obtained concerning the removal of the compounds of interest through the Fenton advanced oxidation process.

Kinetics of acid blue 40 dye degradation under solar light in the presence of CuO nanoparticles synthesized using Citrullus lanatus seeds extract

Abstract In view of eco-benign nature of green synthesis, in the present investigation, the CuO NPs are prepared using Citrullus lanatus seeds extract and photocatalytic degradation efficiency for Acid Blue 40 (AB-40) was evaluated. The CuO NPs were characterized by XRD (X-ray diffraction), SEM (scanning electron microscopy), EDX (energy dispersive X-ray), and FT-IR (Fourier transform infrared) techniques. The synthesized CuO NPs was in face centered monoclinic crystalline form with particle size in 40–60 nm range. The photocatalytic degradation potential of CuO NPs was assessed for acid blue 40 (AB-40) dye degradation and catalyst dose, concentration of dye, radiation exposure time and pH are considered for dye removal. The CuO NPs exhibited auspicious efficiency, an 84.89% dye removal was attained at optimal conditions and dye degradation followed BMG (Behnajady–Modirshahla–Ghanbery) kinetics model. Results revealed CuO NPs synthesized using C. lanatus seeds extract is photoactive catalyst and green route can be employed for CuO NPs fabrication for photocatalytic applications.

Kinetic modelling of dumpsite leachate treatment using Musa sapientum peels as bio-sorbent

Kinetics models are very vital to dumpsite operators and planners as they provide relevant information for effective treatment of leachates. The aim of this work is to model the kinetic process of treatment of Lagos dumpsite leachate using Musa sapientum peels as bio-sorbent with a view of establishing the kinetic parameters of the treatment process. Musa sapientum peels which were collected from Ayetoro market in Epe Local Government area of Lagos State were used to prepare the bio-sorbent. Kinetic process was carried out using 1 g of the prepared bio-sorbent in 100 ml Lagos dumpsite leachate in different conical flasks and at various contacting time. The kinetic data obtained were fitted to different kinetics models. The kinetics models tested were Fractional power model, Lagregren pseudo first – order model, Pseudo second – order model, Kuo – Lotse kinetic model, Blanchard kinetic model and Elovich kinetic model. Other kinetics models considered were Sobkowsk – Czerwi kinetic model, Intraparticle diffusion (IPD) model, Behnajady – Modirshahla – Ghanbery (BMG) model and Diffusion – Chemisorption model. Coefficient of determination (R2) values and the expected nature of the plots of the models were used to screen the tested models. The results revealed that the Pseudo second – order kinetic model has the best R2 value of 0.99996 and the graph followed the expected nature of the plot hence it was adopted in this work. It was concluded that Pseudo second – order kinetic model can be used to navigate the treatment process of Lagos dumpsite using Musa sapientum peels as bio-sorbent.

Enhanced Biogas Production from Sugarcane Vinasse using Electro-Fenton as Pre-treatment Method

High concentration of organic matter in the sugarcane vinasse is potential as a biogas feedstock, but its a very high organic matter (expressed by chemical oxygen demand (COD), >100,000 mg/L) disturbs the biological activity during anaerobic digestion (AD). The maximum COD concentration in vinasse that is recommended as an initial condition of biogas feedstock is ±75,000 mg/L. Furthermore, complex characteristics of vinasse make it necessary to be pre-treated before it is converted to biogas. Therefore, an advanced oxidation process (AOP) such as electro-Fenton (EF) is applied as a pre-treatment method in the AD of vinasse. The goal of this study was to investigate the effect of pre-treatment of vinasse using the EF method on biogas production. The process of EF was conducted with a variation of voltage (4, 6, 8 V) under the batch system and constant operating conditions such as treatment time, initial pH, the ratio of [H2O2] to [COD], and distance between electrodes. Moreover, the process of AD was run using anaerobic digesters having a volume of 2 L under the batch system at room temperature. The AD was conducted for 40 days. The results showed that the best EF could decrease the COD as much as 81.14% at 4 V with constant operation conditions (treatment time of 60 min, initial pH of 4.34, a ratio of [H2O2] to [COD] of 0.6 and distance electrodes of 3 cm). Furthermore, the pre-treatment of EF increased biogas volume successfully (6.02 L). The applicability of the first-order, second-order, and Behnajady-Modirshahla-Ghanbery (BMG) was investigated to evaluate the removal of the COD value. This primary concern is that the electro-Fenton treatment is favorable to decrease the organic matter of sugarcane vinasse.

Coal fly ash-based copper ferrite nanocomposites as potential heterogeneous photocatalysts for wastewater remediation

Coal fly ash (CFA) based-copper ferrite nanocomposites were fabricated, characterized, and applied for the photocatalytic degradation of Methyl Orange (MO) dye. The hydrothermal synthesis route was opted for the fabrication of pristine copper ferrite nanoparticles and its CFA nanocomposites. The prepared photocatalysts were analyzed in terms of structural, surface morphology, chemical state analysis, elemental composition, and optical response. The photocatalytic activity of nanocomposites was investigated sequentially under ultraviolet light (254 nm) and influencing parameters (pH, H2O2 dose, photocatalyst content, dye initial concentration, irradiation time) were studied. The optimized conditions for photocatalytic degradation were found at pH = 5, composite dose = 100 mg/L, H2O2 = 10 mM using CFA nanocomposite and the dye was efficiently degraded within 60 min. The best degradation efficiency of ~98% was achieved using CFA-CuFe2O4 (1:1) under the optimized conditions. The key reactive species (OH, h+, and e−) for photocatalytic degradation were determined by a radical scavenging experiment and OH radicals were found to be the most effective ones. The kinetic study of Fenton oxidation processes was conducted using Behnajady-Modirshahla-Ghanbery (BMG) kinetic model. Response surface methodology was the statistical tool for the assessment of interaction effect among experimental variables.

Classical‐Fenton and Photo‐Fenton oxidation of wastewater arising from cosmetic automobile care products

AbstractThe goal of the study is to investigate Classical‐Fenton and Photo‐Fenton oxidation from Fenton‐based advanced oxidation processes for wastewater treatment arising from cosmetic automobile care products. The main factors that affected Fenton processes (pH, H2O2 doses, Fe2+ doses, and H2O2/Fe2+ ratios) were examined to optimize the operating conditions in batch reactors. The optimal pH values for both systems were found as 3. The optimum experimental conditions were determined as 300 mg/L of Fe2+ dosage, 1050 mg/L of H2O2 dosage and 600/300 of H2O2/Fe2+ ratios for Classical‐Fenton; 300 mg/L of Fe2+ dosage, 900 mg/L of H2O2 dosage, and 600/300 of H2O2/Fe2+ rates for Photo‐Fenton process. In all these cases, COD removals were obtained as 75% in Classical‐Fenton process and around 85% in Photo‐Fenton process. The kinetic model results indicated that the experimental data was represented well by Behnajady–Modirshahla–Ghanbery model (R2 = 0.99) for both Fenton processes. Finally, it is concluded that Classical‐Fenton and Photo‐Fenton processes were effective for COD removal from cosmetic wastewater. Photo‐Fenton process as an oxidative removal process was exhibited more promising results due to rapid degradation, higher removal performance, fewer reagents usage, simple handling, and protecting of process effectiveness.

Treatability of five micro-pollutants using modified Fenton reaction catalysed by zero-valent iron powder (Fe(0))

Diuron, gabapentin, sulfamethoxazole, terbutryn and terbuthylazine are emerging micro-pollutants with concentrations in water and wastewater ranging from tens of ng/L to >10 μg/L levels. The Fenton oxidation catalysed either by zero-valent iron (Fe(0)) or by Fe(II) salts was studied to treat the targeted micro-pollutants and their mixtures at compound concentrations between 1 and 1000 µg/L. The Fe(0)-catalytic Fenton oxidation exhibited complete degradation of all micro-pollutants at initial solution pH 3 but at pH 5, the degradation was 90% for diuron, 80% for gabapentin, 95% for sulfamethoxazole, 100% for terbutryn and 70% for terbuthylazine, respectively. Moreover, dissolved organic carbon in multiple micro-pollutant solutions can be reduced by 70% at pH 3 and 46% at pH 5, which were much better than Fe(II)-catalytic Fenton reaction for the same pH conditions. SEM/EDX analysis showed the corrosion of iron surface and FTIR analysis evidenced the adsorption of oxidation by-products onto solid iron surface. Additionally, the toxicity of effluent after the treatment was reduced to minimal and the Behnajady-Modirshahla-Ghanbery (BMG) model fitted well to the kinetics of the mineralisation of the studied micropollutants. Finally, Fe(0) catalyst can be reused up to three times and the process produced no or less sludge at pH 3 and pH 5, respectively. The impact of this study is that the Fe(0)-catalytic Fenton oxidation would be an alternative to the traditional Fenton reaction to combat the environmental issues caused by the emerging micro-pollutants.

Electro-oxidation and solar electro-oxidation of commercial carbamazepine: effect of the support electrolyte

ABSTRACT Carbamazepine (CBZ) is an anticonvulsant pharmaceutical that is resistant to photodegradation and biodegradation in conventional wastewater treatment plants. In this research, the degradation of commercial CBZ was studied using a boron-doped diamond-Fe system in continuous flow. A response surface model was created to determine the contributions of the current intensity (0.39, 0.50, 0.75, 1.00, and 1.10 A) or current density (1.69, 2.16, 3.25, 4.33, and 4.76 mA/cm2, respectively), support electrolyte (NaCl and CaCl2), and initial CBZ concentration ([CBZ]0) (0.1, 1.0, 5.5, 10.0, and 11.8 mg/L). The highest CBZ removal (%) was achieved with NaCl as a support electrolyte at a current intensity of 0.64 A (2.77 mA/cm2) and [CBZ]0 of 4.5 mg/L at a neutral pH (6–7) and a treatment time of 120 min. The electro-oxidation (EO) process achieved a removal efficiency of 77.25%, whereas solar EO removed 90.77% of CBZ in the presence of ultraviolet radiation (536.37 W/m2). CBZ degradation was fitted to the Behnajady–Modirshahla–Ghanbery kinetic model with constant values of 1/m = 0.31 and 1/b = 0.93, thereby indicating the fast decomposition of CBZ. The toxicity was significantly reduced in the effluent.

Graphene oxide nanocomposite with CuSe and photocatalytic removal of methyl green dye under visible light irradiation

In sight of promising catalytic activity of composite materials, present investigation was designed to prepare the composite of copper selenide nanoparticles and graphene oxide (CuSe/GO) by hydrothermal route. The properties of the prepared material was studied using X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), Scanning electron microscopy (SEM) and UV–Visible techniques. The catalytic activity of CuSe/GO was monitored selecting methyl green (MG) dye as model and effect of irradiation time, catalyst dose, dye initial concentration and pH was studied on dye degradation. The CuSe showed promising photocatalytic activity (PCA) and up to 81% dye removal was realized at pH 5, 0.025 g catalyst dose (CuSe), 30 mg/L dye concentration within 45 min of irradiation, which was increased to 89% in case of CuSe/GO under similar conditions. The MG dye degradation followed Behnajady-Modirshahla-Ghanbery (BMG) kinetics model. Under the existing situation of water pollution, there is a need to improve and apply efficient materials for the treatment of dyes. The CuSe/GO have potential as a photocatayst and can be functional for the removal of dyes in the effluents.

Copper phosphide: A dual-catalysis-center catalyst for the efficient activation of peroxydisulfate and degradation of Orange II

In this study, copper phosphide (Cu3P) was used as a heterogeneous catalyst for peroxydisulfate (PDS) activation and Orange II degradation. This catalyst functions over a broad pH range, from 3.0 to 9.0 and the degradation rate of Orange II is 95.2% at 15 min under optimal conditions. The rapid degradation kinetics can be described by the Behnajady-Modirshahla-Ghanbery (BMG) equation. Sulfate radical, the main reactive oxidizing species, along with OH and O2−, were responsible for pollutant degradation. The Cu3P catalyst exhibited good stability and excellent anti-interference performance toward Cl−, NO3−, and HCO3− anions. The removal efficiency of Orange II remained close to 100%, even after five rounds of recycling reactions. The rapid catalytic mechanism of Cu3P is attributed to the dual-catalysis center in Cu3P (Cu and P) and simultaneous existence of three cycles (CuII → CuIII → CuII, CuI → CuII → CuI, and Cuδ+ → Cu1+δ+ → Cuδ+) on the surface and interior of Cu3P. This study sheds new light on the fabrication of high-performance heterogeneous catalysts to solve the environmental problems.

Facile synthesis of zero valent iron and photocatalytic application for the degradation of dyes

In the present investigation, Zero valent iron (ZVI) was synthesized using ferrous sulfate and borohydrate in the presence of EDTA and characterized by x-ray Diffraction (XRD), Energy-dispersive x-ray (EDX) and Scanning electron microscope (SEM) techniques. The prepared ZVI catalytic activity was evaluated by degrading Acid Red 1 (AR1) and Acid Green 25 (AG25) dyes. The process variables such as pH, initial dye concentration, ZVI dose, contact time, hydrogen peroxide (H2O2) and temperature were optimized for maximum dye degradation. AG25 removal was 98% at pH 4, ZVI dose 0.2 g l−1, initial dye concentration 50 mg l−1, 90 min reaction time and 8 mM H2O2 concentration, whereas pH 2, ZVI dose 0.1 g l−1, 50 mg l−1 initial dye concentration, 8 mM H2O2 and 90 min were found to be optimum for AR1 maximum degradation of 91.60%. Behnajady–Modirshahla–Ghanbery kinetic model and thermodynamic study revealed the spontaneity and endothermic nature of the process. Results revealed that ZVI has potential to degrade the dyes and could possibly be used for the degradation of dyes in wastewater.

Degradation of mixed dye via heterogeneous Fenton process: Studies of calcination, toxicity evaluation, and kinetics.

In this study, the degradation of mixed dye (mixture of Azure B and Congo red) was investigated using iron-loaded black soil as a catalyst via Fenton process. Iron-loaded black soil catalyst was prepared by the wet impregnation method, calcined at different temperatures with varying of iron loading on black soil. Their behavior was compared through characterization techniques (FTIR and XRD). Separately, the effect of calcination and aging of catalyst was investigated on the degradation of mixed dye with optimized conditions. Significant degradation (>90% only in 10min) was observed in optimum conditions. Toxicity measurement was done by a seed germination test which gave significant results. In the kinetic study, it was found that Behnajady-Modirshahla-Ghanbery (BMG) model was the best suited for this process compared to other models. In addition, thermodynamic properties (Gibbs free energy [∆G], activation energy [Ea ], activation enthalpy [∆H], and activation entropy [∆S]) were also calculated. The stability of synthesized catalyst was found to be satisfactory. PRACTITIONER POINTS: Application of Iron-loaded black soil catalyst Mixed dye degradation and toxicity measurement Thermodynamic property studies.

Sludge-based activated carbon catalyzed H2O2 oxidation of reactive azo dyes

ABSTRACT Sludge-based activated carbon (ZAC) was successfully employed as both adsorbent and catalyst for the oxidation process of reactive yellow 86 (RY86) and reactive black 5 (RB5). Physicochemical properties of the prepared sewage sludge-derived activated carbon were evaluated by N2 adsorption/desorption, Fourier transform infrared spectroscopy (FT-IR) and scanning electron microscopy (SEM). The effects of parameters such as initial pH, H2O2 concentrations, ZAC dosages, dye concentrations and temperature on the removal of RY86 and RB5 were investigated. Kinetics results showed that the adsorption rates of RY86 and RB5 by ZAC can be approximated by the pseudo-first order model, and that the oxidation rates by Behnajady–Modirshahla–Ghanbery (BMG) model. Under the optimum conditions in the experiment, i.e. pH = 6.0, T = 303 K, [H2O2] = 49.5 mmol/L, [ZAC] = 4 g/L, [dyes] = 300 mg/L and t = 150 min, 99%, 88% and 84% of colour, COD and TOC were removed by Fenton -like oxidation for RY86, while for RB5, the three removal rates were 90%, 70% and 62%, respectively, indicating that sludge-based activated carbon can be used as an effective catalyst to oxidation of dyes by H2O2 from coloured wastewater.

Degradation of Organic Dyes over Fenton-Like Cu2O–Cu/C Catalysts

A copper-based catalyst supported on carbon microspheres prepared by using the spray drying method has exhibited interesting Fenton-like catalytic properties for the degradation of Methyl Orange, Methyl Blue, and Rhodamine B in aqueous solution. X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS) data suggested that the catalyst consisted of copper particles covered by cuprous oxide. The influence of initial pH, reaction temperature, dosage of catalyst, and H2O2 concentration on the catalyst performance were investigated. Under optimum reaction conditions, the Behnajady–Modirshahla–Ghanbery kinetics model was observed to fit well with the experimental data. It was also observed that hydroxyl radical (HO•) formed from the reaction between hydrogen peroxide (H2O2) and cuprous (Cu+) species was responsible for the dye degradation under acidic conditions. This work provides new insights into the mechanism and kinetics of low-valence copper–carbon composite Fenton-like catalyst for degrading org...

Experimental evaluation of Reactive Yellow 17 degradation using UV light and iron ions activated peroxydisulfate: Efficiency and kinetic model

In the present study, the degradation of Reactive Yellow 17 (RY17) azo dye in aqueous solution was performed using UV light and iron ions as activators of peroxydisulfate (S2O82− or PDS). The effect of several parameters affecting the degradation process was studied and the optimum conditions are found to be: [RY17] = 10 mg/L, [Fe2+] = 0.05 mM, [S2O82−] = 1 mM and the pH = 3. The obtained results showed that the removal degrees of RY17 using different processes such as S2O82−/Fe2+, S2O82−/UV and S2O82−/Fe2+/UV was 63.3%, 81.0% and 95.4% respectively within 20 min of the degradation. Based on theses removal degrees, the degradation efficiency of the RY17 increases in the order: S2O82−/Fe2+/UV > S2O82−/UV > S2O82−/Fe2+ > UV > S2O82−. The experimental data were analyzed using the first-order, second-order and Behnajady-Modirshahla-Ghanbery (BMG) kinetic models, and the kinetic data were in good agreement with the BMG model. Under the optimal conditions, the comparative study of the RY17 degradation using two salts Na2S2O8 and K2S2O8 showed a strong similarity. The total mineralization was monitored using COD and TOC techniques. The results showed that the peroxydisulfate activated by UV and Fe2+/UV system is efficient for the degradation and mineralization of RY17; it could also be an alternative for the treatment of the real wastewater contaminated by azo dyes.

The degradation of landfill leachate in the presence of different catalysts by sonolytic and sonocatalytic processes

ABSTRACTIn the study, the degradation of landfill leachate by single ultrasound (sonolytic) and sonolytic combined with Fe2+ and TiO2 catalysts was carried out in laboratory conditions. The effect of pH and ultrasonic wave amplitude was also investigated in terms of color removal, total organic carbon (TOC) and chemical oxygen demand (COD) from leachate by the sonolytic degradation process. In this process, the color removal efficiency was recorded as 81.81% at 620 nm, pH = 2.0 and 70% wave amplitude. The sonocatalytic degradation of landfill leachate accompanied by different catalysts was studied by using the 70% wave amplitude at pH = 2.0 and room temperature for 20 min. The sonocatalytic degradation of leachate by using Fe2+ and TiO2 was found to be significantly higher than sonolytic degradation (p < 0.05). As the Fe2+ concentration increased from 1.0 to 3.0 mg/L, the COD and color removal of leachate significantly decreased (p < 0.05) from 50 to 35.7% and from 95.5 to 90.9%, respectively. The experimental data obtained from sonocatalytic degradation was analyzed using the Behnajady–Modirshahla–Ghanbery (BMG) kinetic models and found to be compatible. The results showed that the combination of catalyst and sonolysis was a highly effective way to remove color, COD and TOC from landfill leachate.

The Fenton oxidation of biologically treated paper and pulp mill effluents: A performance and kinetic study

Abstract The Fenton oxidation (Fe2+/H2O2) of bio-recalcitrant organics, which are present in biologically treated paper and pulp mill effluents (BTME), were investigated in this study. This study primarily focused on the performance and kinetics involved in the Fenton oxidation of BTMEs. A biologically treated recycle mill effluent (RME) and a neutral sulfite semi-chemical (NSSC) mill effluent were used for the experiments. The impact of FeSO4·7H2O and H2O2 dosages on chemical oxygen demand removal (COD) was evaluated. The Fenton oxidation experiments were carried out at 25 °C and a pH value of 3.8. The initial COD of the biologically treated NSSC and RME effluents were 3756 mg/L and 436 mg/L, respectively. The maximum COD removal was found at a Fe2+/H2O2 ratio of 2.22 and 0.32 for the RME and NSSC effluents, respectively. The optimal COD/H2O2 for the RME and NSSC effluents was found to be 0.96 and 1.19 respectively. After a 60 min reaction, the maximum COD removal efficiency for the NSSC and RME effluents were found to be 44% and 63%, respectively. The maximum reaction rates obtained for the RME and NSSC effluents were 18 mg COD L−1 min−1 and 48 mg COD L−1 min−1, respectively. The experimental results demonstrated that bio-recalcitrant organics, such as phenols and lignin, were readily degraded into organic acids. The applicability of the first order, second order, Behnajady–Modirshahla–Ghanbery (BMG) and a newly developed two staged first-order (TSF) kinetic model were evaluated. Both the BMG and TSF models yielded high correlation coefficients (r2). For extended reaction times, it was found that the TSF model best described the COD removal. In addition, the TSF kinetic constants (k12, k13) revealed that a rapid initial degradation reaction is followed by a slower secondary degradation reaction. This performance and kinetic study demonstrated that the conventional Fenton process can effectively remove bio-recalcitrant organics that are found in BTMEs.