Fenton Oxidation Pre-treatment Research Articles

Sulfomethylation reactivity enhanced the Fenton oxidation pretreatment of bamboo residues for enzymatic digestibility and ethanol production.

Bamboo is considered a renewable energy bioresource for solving the energy crisis and climate change. Dendrocalamus branddisii (DB) was first subjected to sulfomethylation reaction at 95°C for 3h, followed by Fenton oxidation pretreatment at 22°C for 24h. The synergistic effect of combined pretreatment dramatically improved enzymatic digestibility efficiency, with maximum yield of glucose and ethanol content of 71.11% and 16.47g/L, respectively, increased by 4.7 and 6.11 time comparing with the single Fenton oxidation pretreatment. It was found that the hydrophobicity of substrate, content of surface lignin, degree of polymerization, and specific surface area have significant effects on the increase of enzymatic saccharification efficiency. It also revealed that sulfomethylation pre-extraction can improve the hydrophilicity of lignin, leading to the lignin dissolution, which was beneficial for subsequent Fenton pretreatment of bamboo biomass. This work provides some reference for Fenton oxidation pretreatment of bamboo biomass, which can not only promote the utilization of bamboo in southwest China, but also enhances the Fenton reaction in the bamboo biorefinery.

Hydrothermal carbonization of sewage sludge coupled with Fenton oxidation pretreatment: Moderate oxidation to enhance hydrochar yield and properties

Hydrothermal carbonization (HTC) is a promising technology for sewage sludge (SSL) utilization. However, the yield and performance of hydrochar need to be further improved produced when SSL is used as a feedstock must be improved further. Herein, a process combining physicochemical pretreatment, namely, Fenton oxidation (FO) and HTC was developed for SSL utilization. Moderate oxidation was found to improve the yield and performance of the produced hydrochar. The product distribution, yield, and properties of the hydrochar produced using the proposed combined process were compared with those of the hydrochar produced via direct HTC treatment. The pretreatment affected the surface structure and organic composition of SSL and promoted the carbonization of the intermediate products. Thus, compared with the yield of hydrochar (50.7 %) obtained via the direct HTC treatment, the yield of the hydrochar obtained using the combined process increased to 55.0–65.2 % (depending on the pretreatment condition). Hydrochar properties were enhanced using the combined process, and the energy density of hydrochar slightly decreased after pretreatment (1.2–13.1 %); however, the energy yields increased by 0.6–30.1 % due to the enhanced hydrochar yield. The carbonization degree of hydrochar improved, the carbon in the feedstock distributed to the hydrochar increased from 33.40 % to 46.09 %. Moreover, the hydrochar showed more distinct pore channels, slightly improving its combustion activity. This study shows the efficacy of the combined pretreatment–HTC process and provides an experimental basis for the combined hydrothermal treatment of SSL.

Treatment of Aniline Wastewater by Membrane Distillation and Crystallization.

Aniline is a highly toxic organic pollutant with "carcinogenic, teratogenic and mutagenesis" characteristics. In the present paper, a membrane distillation and crystallization (MDCr) process was proposed to achieve zero liquid discharge (ZLD) of aniline wastewater. Hydrophobic polyvinylidene fluoride (PVDF) membranes were used in the membrane distillation (MD) process. The effects of the feed solution temperature and flow rate on the MD performance were investigated. The results showed that the flux of the MD process was up to 20 L·m-2·h-1 and the salt rejection was above 99% under the feeding condition of 60 °C and 500 mL/min. The effect of Fenton oxidation pretreatment on the removal rate of aniline in aniline wastewater was also investigated, and the possibility of realizing the ZLD of aniline wastewater in the MDCr process was verified.

Treatment of emerging contaminants in simulated wastewater via tandem photo-Fenton-like reaction and nutrient recovery

Nutrient rich wastewater containing emerging organic contaminants was used for struvite synthesis with a novel tandem process with a heterogeneous Fenton oxidation pretreatment.

Co-treatment of landfill leachate with urban wastewater by chemical, physical and biological processes: Fenton oxidation preserves autochthonous bacterial community in the activated sludge process

The impact of Fenton oxidation (FO) and Air stripping (AS) pre-treatments on the bacterial community of a biological activated sludge (B-AS) process for the co-treatment of mature landfill leachate (MLL) and urban wastewater (UWW) was assessed. In this work high-throughput sequencing was used to identify changes in the composition of the bacterial communities when exposed to different landfill leachate's pre-treatments. The combination of FO and AS to increase biodegradability (BOD5/COD) and reduce ammonia concentration (NH3) respectively, allowed to successfully operate the B-AS and effectively treat MLL. In particular, BOD5/COD resulted to be the key factor for bacterial community shifting. The microbiological community of the B-AS, mainly composed by the phylum Bacteroidota (Saprospiraceae, PHOS-HE51, Chitinophagaceae) after FO pre-treatment, shifted to Pseudomonadota (Caulobacteraceae and Hyphomicrobiaceae) when FO was not used. At the same time a drastic reduction in BOD5 removal was observed (90%–58%). On the other hand, high NH3 concentration affected the abundance of the family Saprospiraceae, known to play a key role in the degradation of complex organic compounds in B-AS. The results obtained suggest that a suitable combination of pre-treatments can reduce the negative effect of MLL on the B-AS process, reducing the pressure on autochthonous bacteria and therefore the acclimatization time of the biological process.

Advanced treatment of chicken farm flushing wastewater by integrating Fenton oxidation and algal cultivation process for algal growth and nutrients removal

Algae based wastewater treatment has been considered as the most promising win-win strategy for nutrients removal and biomass accumulation. However, the poor linking between traditional wastewater treatment and algal cultivation limits the achievement of this goal. In this study, a novel combination of Fenton oxidation and algal cultivation (CFOAC) system was investigated for the treatment of chicken farm flushing wastewater (CFFW). Fenton oxidation (FO) was adopted to reduce the excessive ammonia nitrogen, which might inhibit the algal growth. The results showed that single FO pretreatment removed 70.5 %, 96.7 %, 86.1 %, and 96.2 % of TN, TAN, TP, and COD, respectively. The highest biomass (235.8 mg/L/d) and lipid (77.3 mg/L/d) productivities were achieved on optimized CFOAC system after 7 days batch cultivation. Accordingly, the nutrients removal efficiencies increased to almost 100 %. Further fatty acid profile analysis showed that algae grown on optimal CFOAC system accumulated a high level of total lipids (32.8 %) with C16–C18 fatty acid as the most abundant compositions (accounting for over 60.6 %), which were propitious to biodiesel production. In addition, this CFOAC system was magnified from 1 L flask to 50 L horizontal pipe photobioreactor (HPPB) in semi-continuously culture under optimal conditions. The average biomass and lipid productivities were 995.7 mg/L/d and 320.6 mg/L/d, respectively, when cultured at 6 days hydraulic retention time with 1/3 substitution every two days. These findings proved that the novel CFOAC system is efficient in nutrients removal, algal cultivation, and biomass production for advanced treatment of CFFW.

Effects of Fenton oxidation on structural changes of lignin from steam-exploded poplar

Pretreatment of steam-exploded poplar by Fenton oxidation was used to effectively biodegrade lignin. The structure of lignin samples (LS from steam-exploded poplar and LSF from samples further treated by Fenton oxidation) obtained by enzymatic hydrolysis during pretreatment were characterized and compared. The results showed that the demethoxy reaction occurred in the process of Fenton oxidation. GPC results indicated that the weight average molecular weight (Mw) of LSF did not change significantly, indicating that that there was no significant condensation during Fenton oxidation pretreatment. Heteronuclear single quantum coherence nuclear magnetic resonance (HSQC NMR) results suggested that the proportion of the three-unit basic structural units of poplar (H, G, and S) were significantly changed during Fenton oxidation process, and more lignin S units were removed than lignin G units. The content of β-O-4 linkages was lower in LSF (74.0%, as a fraction of β-O-4 + β-5 + β-β) than in LS (78.2%), which indicated that β-O-4 linkages were destroyed to a certain extent during Fenton oxidation process, and the content of total lignin interunit linkages including β-O-4, β−β, and β-5 linkages over total lignin aromatic subunits (Ar%) in LSF was higher, reaching 49.9%.

Desalination of Produced Water by Membrane Distillation: Effect of the Feed Components and of a Pre-treatment by Fenton Oxidation

The treatment of produced waters (by-products of oil and gas extraction) with the innovative process of membrane distillation is challenging, because these highly saline streams contain high concentrations of organic compounds and hydrocarbons that cause membrane wetting and impairment of performance. To design the most compact treatment scheme and with the aim of obtaining an easier management of produced water for reuse purposes, Fenton oxidation is here investigated as a feed pre-treatment that may produce an effluent easily handled by membrane distillation. In high-recovery membrane distillation tests, we systematically investigate the detrimental effects of individual contaminants in a synthetic produced water mimicking the composition of a real sample. The recovery rate depends strongly on the initial salinity, which eventually causes scaling and pore blocking. Surfactants are found to be mainly responsible for membrane wetting, but volatile and hydrophobic organics also spoil the quality of the product water. A Fenton oxidation pre-treatment is thus performed to degrade the target organics, with the aim of enhancing the effectiveness of the following membrane distillation and to improve the quality of the final product. The combined oxidation-membrane distillation scheme has both advantages and limitations, which need to be carefully evaluated and further investigated.

Fenton 산화 전처리를 통한 RO 농축폐수의 생물학적 처리

Fenton 산화 전처리를 통한 RO 농축폐수의 생물학적 처리

Biological Treatment of RO Waste Water by Fenton Oxidation Pre-treatment

Biological Treatment of RO Waste Water by Fenton Oxidation Pre-treatment

Better Lime Purification of Raw Sugar Beet Juice by Advanced Fenton Oxidation Process

ABSTRACTThis work discusses the effects of Fenton oxidation pre-treatment on the lime purification of raw sugar beet juice using iron powder and hydrogen peroxide. During Fenton oxidation, particular attention was paid to the effect of reaction time and dosage of Fenton′s reagent to improve purification indexes of the raw juice throughout the clarification process. The total concentration of lime used for the purification was varied from 4.0 to 16.0 g of CaO/100 mL of juice. The results showed that higher color and total phenolic removal were achieved with an increase in H2O2 dosage and reaction time. At an initial pH of less than 6.2 and H2O2 concentration of 7000.0 ppm, color removal reached 85% and approximately 81% of total phenolic removal was achieved at a reaction time of 30 min (Treatment 5). It suggests that the quantity of CaO required for the efficient juice purification may be decreased from 16.0 g/100 mL for the control juice to approximately 12.0 g/100 mL for the juice obtained from Treatment 5. Fenton oxidation process improved the quality indexes of the purified juice, and can be combined with a conventional clarification process to achieve juice with high purity and low color.

Ultrasound coupled with Fenton oxidation pre-treatment of sludge to release organic carbon, nitrogen and phosphorus

We focused on the effects of ultrasound and Fenton reagent in ultrasonic coupling Fenton oxidation (U+F) pre-treatment processes on the disintegration of wastewater treatment plant sludge. The results demonstrated that U+F treatment could significantly increase soluble COD, TOC, total N, proteins, total P and PO43− concentrations in sludge supernatant. This method was more effective than ultrasonic (U) or Fenton oxidation (F) treatment alone. U+F treatment increased the soluble COD by 2.1- and 1.4-fold compared with U and F alone, respectively. U+F treatment increased the total N and P by 1.7- and 2.2-fold, respectively, compared with F alone. After U+F treatment, sludge showed a considerably finer particle size and looser microstructure based on scanning electron microscopy, and the highest OH signal intensity increased from 568.7 by F treatment to 1106.3 using electron spin resonance. This demonstrated that U+F treatment induces disintegration of sludge and release of organic carbon, nitrogen and phosphorus better.

Ultrasound Coupled with Fenton Oxidation Pre-Treatment of Sludge to Release Organic Carbon, Nitrogen and Phosphorus

We focused on the effects of ultrasound and Fenton reagent in ultrasonic coupling Fenton oxidation (U+F) pre-treatment processes on the disintegration of wastewater treatment plant sludge. The results demonstrated that U+F treatment could significantly increase SCOD, TOC, total N, proteins, total P and PO43- concentrations in sludge supernatant. This method was more effective than ultrasonic (U) or Fenton oxidation (F) treatment alone. U+F treatment increased the SCOD by 2.1-and 1.4-fold compared with U and F alone, respectively. U+F treatment increased the total N and P by 1.7-and 2.2-fold, respectively, compared with F alone. This demonstrated that U+F treatment induces disintegration of sludge and release of organic carbon, nitrogen and phosphorus better.

A comparative study of ultrasonication, Fenton's oxidation and ferro-sonication treatment for degradation of carbamazepine from wastewater and toxicity test by Yeast Estrogen Screen (YES) assay

A comparative study of ultrasonication (US), Fenton's oxidation (FO) and ferro-sonication (FS) (combination of ultrasonication and Fenton's oxidation) advanced oxidation processes (AOPs) for degradation of carbamazepine (CBZ) from wastewater (WW) is reported for the first time. CBZ is a worldwide used antiepileptic drug, found as a persistent emerging contaminant in many wastewater treatment plants (WWTPs) effluents and other aquatic environments. The oxidation treatments of WW caused an effective removal of the drug. Among the various US, FO and FS pre-treatments carried out, higher soluble chemical oxygen demand (SCOD) and soluble organic carbon (SOC) increment (63 to 86% and 21 to 34%, respectively) was observed during FO pre-treatment process, resulting in higher removal of CBZ (84 to 100%) from WW. Furthermore, analysis of by-products formed during US, FO and FS pre-treatment in WW was carried out by using laser diode thermal desorption-atmospheric pressure chemical ionization (LDTD-APCI) coupled to tandem mass spectrometry (MS/MS). LDTD-APCI–MS/MS analysis indicated formation of two by-products, such as epoxycarbamazepine and hydroxycarbamazepine due to the reaction of hydroxyl radicals (OH) with CBZ during the three types of pre-treatment processes. In addition, the estrogenic activity of US, FO and FS pre-treated sample with CBZ and its by-products was carried out by Yeast Estrogen Screen (YES) assay method. Based upon the YES test results, none of the pre-treated samples showed estrogenic activity.

Effect of ultrasonication and Fenton oxidation on biodegradation of bis(2-ethylhexyl) phthalate (DEHP) in wastewater sludge

The presence of bis(2-ethylhexyl) phthalate (DEHP) and its metabolites, i.e. 2-ethylhexanol, 2-ethylhexanal, and 2-ethylhexanoic acid in wastewater sludge (WWS) were investigated during aerobic digestion and Bacillus thuringiensis (Bt)-based fermentation of WWS. Ultrasonication and Fenton oxidation pre-treatment was applied to improve biodegradability of WWS and bioavailability of the target compounds for digestion and fermentation. DEHP and 2-ethylhexanoic acid were observed at higher concentration, meanwhile 2-ethylhexanol and 2-ethylhexanal were observed at lower concentration in WWS. After 20-day aerobic digestion, DEHP removal was 72%, 89%, and 85%, and 2-ethylhexanoic acid removal was 71%, 84%, 79%, respectively for raw, ultrasonicated, and Fenton-oxidized sludges. Bt was found to degrade DEHP, leading to DEHP removal of 21%, 40%, and 30%, respectively for raw, ultrasonicated, and Fenton-oxidized sludges in the fermentation. The results suggested that aerobic stabilization and Bt-based fermentation can remove the phthalates, and pre-treatment of WWS was also effective in improvement of DEHP biodegradation. Hence, Bt-based biopesticide production from WWS can be applied safely when taking into consideration the phthalate contaminants.

Optimization of Fenton oxidation pre-treatment for B. thuringiensis – Based production of value added products from wastewater sludge

Fenton oxidation pretreatment was investigated for enhancement of biodegradability of wastewater sludge (WWS) which was subsequently used as substrate for the production of value- added products. The Response surface method with fractional factorial and central composite designs was applied to determine the effects of Fenton parameters on solubilization and biodegradability of sludge and the optimization of the Fenton process. Maximum solubilization and biodegradability were obtained as 70% and 74%, respectively at the optimal conditions: 0.01 ml H 2O 2/g SS, 150 [H 2O 2] 0/[Fe 2+] 0, 25 g/L TS, at 25 °C and 60 min duration. Further, these optimal conditions were tested for the production of a value added product, Bacillus thuringiensis (Bt) which is being used as a biopesticide in the agriculture and forestry sector. It was observed that Bt growth using Fenton oxidized sludge as a substrate was improved with a maximum total cell count of 1.63 × 10 9 CFU ml −1 and 96% sporulation after 48 h of fermentation. The results were also tested against ultrasonication treatment and the total cell count was found to be 4.08 × 10 8 CFU ml −1 with a sporulation of 90%. Hence, classic Fenton oxidation was demonstrated to be a rather more promising chemical pre-treatment for Bt - based biopesticide production using WWS when compared to ultrasonication as a physical pre-treatment.

Influence of ultrasonication and Fenton oxidation pre-treatment on rheological characteristics of wastewater sludge

The effect of ultrasonication and Fenton oxidation as physico-chemical pre-treatment processes on the change of rheology of wastewater sludge was investigated in this study. Pre-treated and raw sludges displayed non-Newtonian rheological behaviour with shear thinning as well as thixotropic properties for total solids ranging from 10 g/L to 40 g/L. The rheological models, namely, Bingham plastic, Casson law, NCA/CMA Casson, IPC Paste, and power law were also studied to characterize flow of raw and pre-treated sludges. Among all rheological models, the power law was more prominent in describing the rheology of the sludges. Pre-treatment processes resulted in a decrease in pseudoplasticity of sludge due to the decrease in consistency index K varying from 42.4 to 1188, 25.6 to 620.4 and 52.5 to 317.9; and increase in flow behaviour index n changing from 0.5 to 0.35, 0.62 to 0.55 and 0.63 to 0.58, for RS, UlS and FS, respectively at solids concentration 10–40 g/L. The correlation between improvement of biodegradability and dewaterability, decrease in viscosity, and change in particle size as a function of sludge pre-treatment process was also investigated. Fenton oxidation facilitated sludge filterability resulting in capillary suction time values which were approximately 50% of the raw sludges, whereas ultrasonication with high input energy deteriorated the filterability. Biodegradability was also enhanced by the pre-treatment processes and the maximum value was obtained (64%, 77% and 73% for raw, ultrasonicated and Fenton oxidized sludges, respectively) at total solids concentration of 25 g/L. Hence, pre-treatment of wastewater sludge modified the rheological properties so that: (1) the flowability of sludge was improved for transport through the treatment train (via pipes and pumps); (2) the dewaterability of wastewater sludge was enhanced for eventual disposal and; (3) the assimilation of nutrients by microorganisms for further value-addition was increased.

Combined Fenton oxidation and aerobic biological processes for treating a surfactant wastewater containing abundant sulfate

The present study is to investigate the treatment of a surfactant wastewater containing abundant sulfate by Fenton oxidation and aerobic biological processes. The operating conditions have been optimized. Working at an initial pH value of 8, a Fe 2+ dosage of 600 mg L −1 and a H 2O 2 dosage of 120 mg L −1, the chemical oxidation demand (COD) and linear alkylbenzene sulfonate (LAS) were decreased from 1500 and 490 mg L −1 to 230 and 23 mg L −1 after 40 min of Fenton oxidation, respectively. Advanced oxidation pretreatment using Fenton reagent was very effective at enhancing the biodegradability of this kind of wastewater. The wastewater was further treated by a bio-chemical treatment process based on an immobilized biomass reactor with a hydraulic detention time (HRT) of 20 h after Fenton oxidation pretreatment under the optimal operating conditions. It was found that the COD and LAS of the final effluent were less than 100 and 5 mg L −1, corresponding to a removal efficiencies of over 94% and 99%, respectively.