Degradation Of Nonylphenol Research Articles

Microalgae-bacterial consortiums for enhanced degradation of nonylphenol: Biodegradability and kinetic analysis

The widespread use of non-ionic surfactant nonylphenol (NP) has led to significant water pollution, posing a threat to both ecological stability and human health. However, the efficient biodegradation method and system of NP-biodegradation remain complex scientific challenges. In this study, we isolated and characterized three Pseudomonas sp. strains SW-1 (Scenedesmus quadricauda-associated), ZL-2 (Ankistrodesmus acicularis-associated), XQ-3 (Chlorella vulgaris-associated), and one NP-degrading Cupriavidus sp. strain EB-4, which exhibited the ability to utilize NP as the sole carbon source. Furthermore, four consortiums of microalgae-bacterial, S. quadricauda and SW-1 (S-SW), A. acicularis and ZL-2 (A-ZL), C. vulgaris and XQ-3 (C-XQ), S. quadricauda and EB-4 (S-EB), were constructed to investigate their biodegradability and kinetic characteristics of NP degradation from water. The consortiums showed higher degradation efficiency compared to individual microalgae or bacteria. The C-XQ consortium exhibited the highest degradation rate, removing over 94% of NP within just seven days. The first-order model with the following order of degradation rate by consortiums was C-XQ (0.3960 d−1) > S-SW (0.3506 d−1) > A-ZL (0.1968 d−1) > S-EB (0.1776 d−1). Compared with the results of our previous study, the interaction between microalgae and bacteria is not a simple additive relationship. Our findings highlight the potential of an algal-bacterial consortium for the remediation of NP-contaminated environments.

Formation and estimated cytotoxicity of trihalomethanes and haloacetic acids during ozonation of nonylphenol in bromide-containing water after chlorination process: Impact of ozonation initial pH

The presence of nonylphenol (NP) in bromide-containing water contributed to the formation of regulated disinfection by-products (DBPs): trihalomethanes-4 (THM4) and haloacetic acids-5 (HAA5). This study investigates the effects of ozonation pH on the degradation of NP, DBP formation, and DBP-estimated cytotoxicity. The ozonation pH was varied to 5, 7, and 9 to determine the effect of acidic, neutral, and alkaline conditions. The increase of ozonation initial pH improved the NP degradation. Ozonation of all initial pH conditions could decrease TCM, BDCM, and BDCM formation but increase the TBM formation at alkaline conditions. The formation of mono-HAA5 on the other hand, increased at all ozonation initial pH. Ozonation at acidic and neutral initial conditions can reduce the estimated cytotoxicity of the total formation of THM4 and HAA5 by 74.34 % and 93.31 %, respectively. In contrast, DBP's estimated cytotoxicity was raised by 33.72 % upon ozonation at an initial pH of alkaline. According to the study's findings, lowering the cytotoxicity of DBPs in acidic or alkaline environments can be achieved without changing the ozonation's pH. Based on these findings, pH changes are not required to reduce DBP during ozonation of NP-bromide-containing water. Future research on the impact of natural organic matter is recommended to investigate ozonation's capacity to reduce DBP production during ozonation of NP-containing natural water.

Effect of organic carbon structures on the degradation of nonylphenol by hydrogen peroxide in sediment-water system.

A laboratory experiment is conducted to investigate the effects of organic carbon (OC) from riverine and marine sediments on the degradation of ring-14 C-labeled nonylphenol (14 C-NP) by hydrogen peroxide (H2 O2 ). Researchers have isolated demineralized OC (DM) before and after oxidation, namely, DM and resistant OC (ROC) fractions, respectively. The structures of DM and ROC are characterized using solid-state 13 C nuclear magnetic resonance. Unstable structures (O-alkyl, OCH3 /NCH, and COO/NC=O) show a significant and positive correlation with the degradation of 14 C-NP (R2 >0.73, p<0.05), thus suggesting that the NP absorbed in the unstable structures is easily degraded because of the decomposition of unstable components. The stable structures (alkyl C and non-protonated aromatic C [Arom C─C]) exhibit a significant and negative correlation with the degradation of 14 C-NP (R2 >0.69, p<0.05), thus suggesting that the NP absorbed and protected in these resistant structures is minimally degraded. The significant correlations among the degradation kinetic parameters (Frap and Fslow ), OC structures (Falip and Farom ), and microporosity further illustrate the important protective roles of OC structures and micropores in the degradation of 14 C-NP by H2 O2 (R2 >0.69, p<0.05). The parent NP fraction that desorbed into the aqueous solution or extracted is completely degraded, indicating preferential degradation of the easily desorbed NP. This study provides important insights into the NP degradation mechanism in sediment-water systems, particularly regarding sediment OC structures and microporosity.

Effects of sedimentary organic matter degradation and structure on nonylphenol degradation by sodium persulfate

The structure and constituents of sedimentary organic matter (SOM) in the degradation of benzene ring-14C labeled 4-nonylphenol (14C-NP) by sodium persulfate (Na2S2O8) were investigated. Na2S2O8 mineralized over 84 % of 14C-NP to 14CO2, and no parent unlabeled 4-nonylphenol (NP) compounds were detected in the water-soluble/supernatant phase or extractable residues. Organic carbon (OC) was sequentially separated from six sediment samples collected from the Pearl River (BET), estuary (GSD), continental shelf (S11 and S21), and deep sea (M9 and M10). Demineralized OC (DM), unstable OC (USOC), nonhydrolyzable OC (NHC), and resistant OC (ROC) were obtained and characterized using solid-state 13C nuclear magnetic resonance (SS-NMR). The correlations among USOC, NHC, and the degradation kinetic constant of 14C-NP (kNP) were significant (R2 > 0.86, p < 0.01), indicating that USOC and NHC were the main factors controlling 14C-NP degradation. SOM structure and constituent analyses indicated that O-alkyl C + OCH3/NCH C + COO/NC=O C and carbohydrate + protein were positively related to Ln(kNP) (R2 > 0.72, p < 0.05) because these structures were unstable. However, the stable structures (Alkyl C and Arom CC) and constituents (sporopollenin, algaenan, and char) hindered 14C-NP degradation because they were negatively related to Ln(kNP) (R2 > 0.81, p < 0.05). The OC removal rate was positively correlated with 14C-NP degradation (R2 > 0.86, p < 0.01), indicating that the NP was primarily degraded in parallel with the breakdown of SOM. Stoichiometric analysis showed that Na2S2O8 effectively oxidized over 58 % of the OC to CO2, and the electron transfer efficiency was 17.2–69.5 %. This study is the first to emphasize the importance of SOM degradation, structure, and constituents in the degradation of NP by persulfate.

Efficient elimination of nonylphenol and 4-tert-octylphenol by weak electrical stimulated anaerobic microbial processes

The investigation into the degradation of alkylphenol pollutants (APs) has become a hotspot due to their harmful effects on the environment and human health. In this study, microbial electrolysis cells (MECs) were used to degrade nonylphenol (NP) and 4-tert-octylphenol (4-tert-OP). The study found that the degradation rates of NP and 4-tert-OP for a 6-day period were 83.6% and 96.3%, respectively, which were 30.53% and 26.7% higher than those of the group without applied voltage. The double layer area in the degradation of 4-tert-OP was larger than that of NP, and the resistance exhibited by 4-tert-OP (87.47 Ω) in MEC was lower than that of NP (99.42 Ω). Meanwhile, NP had a greater effect on the bioenzyme activity than 4-tert-OP. GC-MS analysis showed that the degradation pathways of both pollutants mainly included oxidation and hydroxylation reactions. Furthermore, the microbial community analysis indicated that the main functional bacteria in NP degradation were Citrobacter, Desulfovibrio and Advenella, and those in 4-tert-OP degradation were Stenotrophomonas, Chryseobacterium, Dokdonella, and the key microbiomes underlying the cooperative relationship. The biotoxicity test indicated that the toxicity of residual substances was significantly reduced. Therefore, the MEC system is efficient and environmentally friendly and has broad application prospects in phenol refractory organics.

Long-Chain Alkylphenols Biodegradation Potential of the Soil &lt;i&gt;Ascomycota&lt;/i&gt;

A total of 11 strains ascomycetes-destructors of technical nonylphenol (NP) and 4-tert-octylphenol (4-t-OP) were isolated from nonylphenol-contaminated soddy-podzolic loamy soil (Leningrad Region, Russia). Fungal isolates are able to degrade NP and 4-t-OP at a high load (300 mg/L). The most effective Fusarium solani 8F strain has the ability to degrade alkylphenols (AP) both under cometabolic conditions and without additional carbon and energy sources. The decrease in AP is due to the processes of biodegradation and/or biotransformation by the studied strain and, to a small extent, due to sorption by fungal cells. The NP and 4-t-OP half-life under cometabolic conditions is 3.5 and 6.4 hours, respectively, and without additional carbon and energy sources, 9 and 19.7 hours, respectively. The amount of the lipid peroxidation product, malondialdehyde, as well as the reduced glutathione content in the process of NP and 4-t-OP biodegradation under cometabolic conditions increases by 1.7 and 2 times, respectively, compared with the control. The high level of reduced glutathione in F. solani 8F cells may indicate the participation of this metabolite both in the processes of AP biodegradation and in providing strain resistance to oxidative stress. To our knowledge, this is the first report on the degradation of NP and 4-t-OP by ascomycetous fungus F. solani both under cometabolic conditions and without additional carbon and energy sources. The revealed high potential of soil ascomycetes to degrade alkylphenols can be the basis for new environmentally safe bioremediation technologies for the purification of endocrine-disruptors conta-minated soils, natural and waste waters.

Pseudomonas aeruginosa improved the phytoremediation efficiency of ryegrass on nonylphenol-cadmium co-contaminated soil.

The effect of Pseudomonas aeruginosa (P. aeruginosa) on the phytoremediation efficiency of ryegrass on soil contaminated with nonylphenol (NP) and cadmium (Cd) was investigated by pot experiments. Pseudomonas aeruginosa application stimulated the adsorption of Cd by ryegrass and facilitated the biodegradation of NP in the soil. Exogenous P. aeruginosa inoculation increased the activities of urease, dehydrogenase, and polyphenol oxidase in the soil of the T4 treatment by 38.5%, 50.0%, and 56.5% compared to that of the T2 treatment, respectively. There was a significant positive correlation between the activities of dehydrogenase and polyphenol oxidase and the NP removal rate (P < 0.001). The relative abundances of beneficial microorganisms (such as Sphingomonas, Lysobacter, Streptomyces, Chloroflexia, Deltaproteobacteria, and Alphaproteobacteria) were increased as a result of P. aeruginosa inoculation. These microorganisms play important roles in nutrient cycling, Cd adsorption, and NP degradation. Additionally, P. aeruginosa was not the dominate bacterial species at the end of the experiment. According to this study, P. aeruginosa application improved the phytoremediation efficiency of ryegrass on soil contaminated with NP and Cd, with a minimal risk of alien microbial invasion.

Metagenomic analysis of microbial community and gene function of anodic biofilm for nonylphenol removal in microbial fuel cells

Nonylphenol as a high priority control of persistent toxic contaminant has been frequently detected in environment. In this study, Dual-chamber microbial fuel cells (MFCs) were constructed for simultaneous nonylphenol degradation and electricity generation; and microbial community and gene function of anodic biofilm were analyzed through metagenomic sequencing. The results showed that nonylphenol removal rate reached 82% within 60 h in MFCs, and the maximum voltage achieved 0.60 V when the external resistance was 1000 Ω. Metagenomics analysis showed that Proteobacteria and Actinobacteria were dominant phyla in biofilm attached to anode. At genus level, the relative abundance of Streptomyces (21.45%), Microbacterium (11.96%), Burkholderia (10.90%), Pusillimonas (7.59%), Stenotrophomonas (6.62%), Pseudomonas (4.44%), Nitrospirillum (3.75%), Nocardia (1.73%), Arthrobacter (1.71%) and Bacillus (1.21%) were remarkably higher than those of control groups. In terms of functional genes annotation, a relatively high gene number was focus on various metabolic pathways (such as carbon metabolism, riboflavin metabolism, and nitrogen metabolism) during MFCs operated. The metabolic pathways of nonylphenol were suggested to divide into the oxidation of aromatic ring (route-1) and the fission of alkyl chain (route-2) based on KEEG analysis.

Novel nonylphenol-degrading bacterial strains isolated from sewage sludge: Application in bioremediation of sludge

Nonylphenol (NP) is an anthropogenic pollutant frequently found in sewage sludge due to the insufficient degrading effectiveness of conventional WWTPs and has attracted attention as an endocrine disruptor. The aim of this study was to isolate specific NP-degrading bacteria from sewage sludge to be used in the degradation of this contaminant through bioaugmentation processes in aqueous solution and sewage sludge. Up to eight different bacterial strains were isolated, six of them not previously described as NP degraders. Bacillus safensis CN12 presented the best NP degradation in solution, and glucose used as an external carbon source increased its effect, reaching DT50 degradation values (time to decline to half the initial concentration of the pollutant) of only 0.9 days and a complete degradation in <7 days. Four NP metabolites were identified throughout the biodegradation process, showing higher toxicity than the parent contaminant. In sewage sludge suspensions, the endogenous microbiota was capable of partially degrading NP, but a part remained adsorbed as bound residue. Bioaugmentation was used for the first time to remove NP from sewage sludge to obtain more environmentally friendly biosolids. However, B. safensis CN12 was not able to degrade NP due to its high adsorption on sludge, but the use of a cyclodextrin (HPBCD) as availability enhancer allowed us to extract NP and degrade it in solution. The addition of glucose as an external carbon source gave the best results since the metabolism of the sludge microbiota was activated, and HPBCD was able to remove NP from sewage sludge to the solution to be degraded by B. safensis CN12. These results indicate that B. safensis CN12 can be used to degrade NP in water and sewage sludge, but the method must be improved using consortia of B. safensis CN12 with other bacterial strains able to degrade the toxic metabolites produced.

Role of the sedimentary organic matter structure and microporosity on the degradation of nonylphenol by potassium ferrate

In this study, the role of organic matter structure and microporosity in the adsorption and degradation of radioactive nonylphenol in sediments treated with potassium ferrate solutions was investigated. The demineralized fractions and acid non-hydrolyzable fractions were isolated and characterized via advanced solid-state 13C nuclear magnetic resonance and CO2 gas adsorption technology, respectively. Radioactive nonylphenol in the sediments was also fractionated into 14CO2, water-soluble residues, extractable residues, and strongly bound residues after treatment with potassium ferrate. A first-order, two-compartment kinetic model well described the mineralization and degradation kinetics of radioactive nonylphenol in the sediment (R2 > 0.99). The degradation percentages of spiked nonylphenol were highly negatively correlated with aromatic carbon, aliphatic carbon, and microporosity estimated from acid-non-hydrolyzable fractions in the bulk sediments (R2 > 0.82, p < 0.01). The percentages of adsorbed parent nonylphenol residues were highly positively correlated with aromatic carbon, aliphatic carbon, and microporosity estimated from acid-non-hydrolyzable fractions in the bulk sediments (R2 > 0.90, p < 0.01). The parent nonylphenol compound desorbed into the aqueous phase and was completely degraded. This study is the first to demonstrate the important role of aromatic carbon, aliphatic carbon, and microporosity in acid non-hydrolyzable fractions on the degradation of nonylphenol during the potassium ferrate oxidation treatment process.

Degradation of the nonylphenol aqueous solution by strong ionization discharge: evaluation of degradation mechanism and the water toxicity of zebrafish.

Nonylphenol (NP) is a typical environmental endogenous disrupter with low concentration and high toxicity. This paper describes the mechanism of NP degradation in solution by strong ionization dielectric barrier discharge (SIDBD). Furthermore, the degradation performance of NP by SIDBD was tested by changing the equipment voltage, the initial concentration of NP in aqueous solution, pH, and inorganic ions. Degradation pathways of NP were detected using a high-performance liquid chromatography-mass spectrometer. The biological effects of NP degradation were assessed by detecting indicators of embryonic development in zebrafish (survival rate, fetal movement, heartbeat, the body length, behavior, deformity) and adult fish (sex differentiation, weight, ovarian testes pathological section analysis). The results showed when the input O2 was 5 L/min and the voltage was 3.2 kV, the degradation efficiency of NP can reach 99.0% after 60 min of experiment. Equipment voltage, initial concentration of NP in solution, pH, inorganic ions and other factors can influence the degradation efficiency of NP by DBD. At the higher concentration of NP, the greater influence on embryonic development in zebrafish was noticed. Although the effects of NP on zebrafish sex differentiation were not obvious, it showed significant male weight inhibition and decrease in sperm number.

Nonylphenol photodegradation by novel ternary MIL-100(Fe)/ZnFe2O4/PCN composite under visible light irradiation via double charge transfer process

Nonylphenol (NP) residues, as a typical endocrine disrupting chemical (EDC), frequently exist in sewage, surface water, groundwater and even drinking water, which poses a serious threat to human health due to its bioaccumulation. In order to remove NP, a series of MIL-100(Fe)/ZnFe2O4/flake-like porous carbon nitride (MIL/ZC) was synthesized through in-situ synthesis at room temperature. High performance of ternary MIL/ZC is used to degrade NP under visible light irradiation. The results show that 30MIL/ZC2 (20 wt.% ZnFe2O4) ternary composite had the best photocatalytic activity (99.84%) when the dosage was 30 mg. Further mechanism analysis shows that the excellent photocatalytic activity of 30MIL/ZC2 could be ascribed to the double charge transfer process between flake-like porous carbon nitride (PCN) and other catalysts in the ternary heterojunction, and the separation of photogenerated electron-hole pairs was more effective. In addition, the 30MIL/ZC2 also showed high stability after five cycles of the photodegradation reaction. Furthermore, the active substance (•O2−) was considered to be the main active substance in the NP degradation process. Based on the research results, the possible photocatalytic reaction mechanism of 30MIL/ZC2 ternary composite was proposed and discussed in detail.

Effects of Fe2O3 nanoparticles on extracellular polymeric substances and nonylphenol degradation in river sediment

In this study, the impact of Fe2O3 nanoparticles (nFe2O3) on microbial extracellular polymeric substances (EPS) and nonylphenol (NP) degradation in sediment were investigated. The results showed that the addition of nFe2O3 lowered the degree of EPS overproduction and the amount of polysaccharides and proteins secreted in NP contaminated sediment. Particularly, the secretion of colloidal EPS (C-EPS) lowered significantly (P < 0.05), and the content of tyrosine-like, tryptophan-like, and soluble microbial by-product-like substances in C-EPS also decreased, leading to a lower aromaticity, humification, and hydrophobicity of C-EPS. Furthermore, with lower C-EPS content in water, NP was adsorbed to sediment more easily, and the weakened toxic effect of NP to bacteria as well as a higher proportion of organic matter degrading microbes stimulated NP degradation. These findings revealed the vital role of nFe2O3 in alleviating NP toxicity to microbes and reducing NP ecological risk in aquatic environments.

Heterogeneous catalytic degradation of nonylphenol using persulphate activated by natural pyrite: response surface methodology modelling and optimisation

ABSTRACT The degradation of nonylphenol polyethoxylates (NPEOs) was investigated by persulphate (PS) activated using naturally pyrite semi-conductor mineral (NP-SCM) in aqueous solutions. The effects of various factors including solution pH, NP-SCM dosage, NPEOs and PS concentration were examined through response surface methodology (RSM) and Box-Behnken design (BBD) technique. The properties of NP-SCM were characterised by FESEM, BET, XRD and EDX analyses. The results showed that the RSM model had a well correlation (R2 > 0.99) between the predicted data and the experimental findings of NPEOs degradation. In addition, under the optimum conditions (PS = 5.85 mM, pH = 3.0, NP-SCM = 0.85 g/L and NPEOs = 10 µM), the removal efficiency of NPEOs reached more than 99%. The maximum removal efficiency of COD and TOC was obtained 87% and 80% at 90 min reaction time, respectively. The negative effect of various competing ions on the removal of NPEOs was as phosphate>bicarbonate>copper>nitrate>calcium>ammonium. After five successive catalyst cycles reuse, the degradation efficiency was insignificantly decreased from 99.6% to 90.5%, which indicated the excellent potential reusability of NP-SCM catalyst. It can be concluded that NP-SCM along with PS, due to the generation of highly reactive oxidising species (SO4 ●-), its simplicity and easy separation of the catalyst, has a great potential for the degradation of NPEOs from aqueous solutions.

Nonylphenol ethoxylates biodegradation increases estrogenicity of textile wastewater in biological treatment systems

The formation of estrogenic intermediates, i.e. nonylphenol diethoxylate (NP2EO), nonylphenol monoethoxylate (NP1EO), and nonylphenol (NP), following nonylphenol ethoxylates (NPEOs) biodegradation in textile wastewater raises concerns about its endocrine disruptive activity, but the estrogenicity changes of textile wastewater throughout biological treatment processes remain unknown. In the present study, the estrogenicity of textile wastewater sampled from 10 wastewater treatment plants (WWTPs) were investigated using the reporter gene-based T47D-KBluc bioassay. Results showed that the estrogenicity of the textile wastewater significantly increased after either anaerobic or aerobic treatment in all WWTPs, with an average fold change of 3.21, although traditional pollutants were effectively removed. The estradiol equivalents of the effluent (ranging from 1.50 to 4.12 ng-E2/L) were generally higher than published effect based trigger values, indicating an increased risk for the receiving waters. Removal efficiency was high (84.46%) for NPEOs, but was low for NP2EO and NP1EO in the biological treatment processes. Nevertheless, NP had increased concentrations after the treatment. Bioanalytical equivalent concentration of the textile wastewater and that of NP2EO, NP1EO, and NP showed a good linear correlation, of which NP alone contributed more than 70% to the observed estrogenicity. Extending hydraulic retention time was found effective in reducing the estrogenicity as it allows relatively complete degradation of NP, which was further confirmed by running lab-scale A/O reactors fed with NP10EO. The results may extend our knowledge regarding the estrogenicity of textile wastewater and its reduction technologies used in WWTPs.

Sono-catalytic activation of persulfate by nZVI-reduced graphene oxide for degradation of nonylphenol in aqueous solution: Process optimization, synergistic effect and degradation pathway

Abstract A hybrid persulfate (PS) activation system based on sonication (US) and nZVI-reduced graphene oxide catalyst (PS/US/nZVI-rGO) was investigated to degrade nonylphenol (NP). Field emission scanning electron microscopy (FESEM), energy-dispersive X-ray spectroscopy mapping (EDX-mapping), X-ray diffraction analysis (XRD) and vibrating sample magnetometer (VSM) analyses confirmed the successful synthesize of nZVI-rGO catalyst. The effect of five independent variables on NP degradation efficiency in the PS/US/nZVI-rGO oxidation system was optimized by a five-level full central composite design (CCD). The Adequacy and validity of the proposed model for predicting NP degradation were confirmed with P-value S O 4 • - ) plays the major role of NP degradation in the PS/US/nZVI-rGO oxidation system. The most abundant reaction intermediates caused by the degradation of NP (m/z = 220) were compounds with m/z

Efficient degradation of nonylphenol and 2,4-dinitrophenol by sunlight responsive hexacyanocobaltates nanostructures

Nonylphenol (NP) and 2,4-dinitrophenol (2,4-DNP) are causing serious environmental concerns owing to their toxic, carcinogenic, persistentancy and bio-accumulating properties. It has been found that their concentrations are abundant near to industries and in many water bodies due to untreated release. Therefore, their complete removals using low-cost, efficient and environmental friendly techniques from water are required. Sunlight active metal hexacyanocobaltates nanoparticles have been reported beneficial heterogeneous and recoverable catalysts. Therefore, a green route based on utilization of natural material (Azadirachta indica leaf extract) and water was developed for the synthesis of cadmium hexacynocobaltate (CdHCC) and manganese hexacyanocobaltate (MnHCC) nanoparticles. Electron microscopic analysis revealed nanometer range (∼100 nm) for CdHCC and MnHCC particles. Synthesized nanomaterials were employed for the degradation of substituted phenols under direct Sunlight to follow the natural scenario. Maximum degradation of selected phenols (CdHCC- NP: 70 %; 2,4-DNP: 77 %, MnHCC- NP: 90 %; 2,4-DNP: 97 %) required 25 mg of catalyst per 50 mg L−1 of phenols at neutral pH under Sunlight irradiation. This excellent photocatalytic activity of the MnHCC might be due to high surface activity (surface areas of CdHCC and MnHCC were 95 m2 g-1 and 448 m2 g-1, respectively) and particles stability (as observed from zeta potential, CdHCF: -13.5 mV; MnHCF: -19.2 mV). The degradations followed first-order kinetics. Adsorption plots were best fitted with Langmuir isotherm. GC–MS analysis of the final reaction mixtures showed the formation of low molecular weight and safer compounds, which were finally mineralized. Degradation mechanism of NP and 2,4-DNP involved OH radicals based oxidation, hydroxylation, and ring-opening. These materials were found reusable up to ten times revealing sustainability. Overall, these Sunlight responsive novel metal hexacyanocobaltate nanomaterials might be promising and sustainable materials for remediation of environmental contaminants.

Insights into nonylphenol degradation by UV-activated persulfate and persulfate/hydrogen peroxide systems in aqueous matrices: a comparative study.

Nonylphenol ethoxylates are widely used industrial surfactants. Once released into environment compartments, these chemicals undergo degradation and generate more toxic short chain artificial compound nonylphenol (NP). The latter is a known endocrine disrupting compound and persistent micropollutant. In the present study, the performance of NP degradation in UV-induced PS, PS/Fe2+, PS/H2O2, and PS/H2O2/Fe2+ systems was examined. The effect of concentration of oxidant and activators on the efficiency of target compound decomposition was studied. The trials were conducted in ultrapure water and groundwater to assess the influence of matrix composition. The obtained results indicated that NP degradation by all the systems studied followed a pseudo-first-order kinetics. The application of UV-activated PS at lower concentrations of the oxidant improved NP oxidation in both water matrices. The addition of iron activator at a cost-effective concentration showed slight improvement in the studied PS-based systems. The application of UV-induced dual oxidant PS/H2O2 system demonstrated promising results in NP oxidation. In turn, the addition of Fe2+ to the UV/PS/H2O2 system accelerated the target compound oxidation at an optimized dose of iron activator. The radicals scavenging studies indicated that HO• was the predominant radical in all UV-induced PS-based systems. The results of this research could provide significant information for the removal of NP from different water matrices by means of UV-induced persulfate-based oxidation processes.

Phytotoxicity, Bioaccumulation, and Degradation of Nonylphenol in Different Microalgal Species without Bacterial Influences.

Nonylphenol (NP) is a contaminant that has negative impacts on aquatic organisms. To investigate its phytotoxicity, bioaccumulation, and degradation in algae without associated bacteria, six freshwater microalgae—Ankistrodesmus acicularis, Chlorella vulgaris, Chroococcus minutus, Scenedesmus obliquus, Scenedesmus quadricauda, and Selenastrum bibraianum—in bacteria-free cultures were studied. When exposed to 0.5–3.0 mg L−1 NP for 4 days, cell growth and photosynthesis, including maximal photochemistry (Fv/Fm), were suppressed progressively. The antioxidant responses of superoxide dismutase (SOD), catalase (CAT), and peroxidase (POD) showed species differences. While the antioxidant enzymes in C. vulgaris and S. obliquus were more active with the increase of NP (0–3 mg L−1), they dropped in the other four algae at concentrations of 1 and 1.5 mg L−1. Therefore, C. vulgaris and S. obliquus were designated as NP-tolerant species and showed more conspicuous and faster changes of antioxidant reactions compared with the four NP-sensitive species. All six species degraded NP, but A. acicularis was more reactive at low NP concentrations (<1 mg L−1), suggesting its possible application in sewage treatment for its potential for effective NP removal from water bodies in a suitable scope. Therefore, the conclusion is that biodegradation of NP by algae is species specific.

Enhanced adsorption and degradation of nonylphenol on electron-deficient centers of photocatalytic surfaces

Boron doped TiO2 was used for enhanced adsorption and degradation of nonylphenol. It was found that boron from boric acid was doped into TiO2 crystal lattice as interstitial boron, introducing more Lewis acidic sites as electron-deficient centers. Further characterization found that boron doping not only improved its Lewis acidity but also enhanced the photocatalytic activity both in light absorption and lifetime of the photogenerated charges. Boron doped TiO2 possessed 1.8 times adsorption capacity over TiO2 due to faster adsorption kinetics, both of which fits Langmuir model. And the adsorption on TiO2 and boron doped TiO2 follows pseudo-first-order and pseudo-second-order, respectively. The adsorption process was further studied using in situ infrared, the results showed phenolic hydroxyl groups was dissociative absorbed on TiO2, while phenolic hydroxyl was coordinated to boron on boron doped TiO2. In two hours of degradation, 99.4% of nonylphenol was removed on boron doped TiO2, the degradation rate of which was 1.5 times that of TiO2. The TOC removal was 89.5%, suggesting most of nonylphenol was mineralized. Proposed degradation pathway showed the degradation mechanism was complicated. The reusability maintained well after three repeating degradation.