Nonylphenol Degradation Rate Research Articles

Research on Degradation Characteristics of Nonylphenol in Water by Highly Effective Complex Microorganisms

Aiming at effectively controlling nonylphenol (NP) pollution, three bacterial strains were isolated from activated sludge and landfill leachate, which could grow with nonylphenol as sole carbon and energy source. The three nonylphenol-degrading bacteria isolated were named as WN6, SLY9 and SLY10, respectively. The morphological observation and 16S rDNA identification revealed that the strains belonged to Serratia sp., Klebsiella sp. and Pseudomonas putida, respectively. WN6 and SLY9 contained ALK gene, while WN6 and SLY10 harbored C12O genes. The three strains were combined together to form complex microorganisms ZJF. The ratio of Serratia sp. to Klebsiella sp. to Pseudomonas putida was 2:1:2 (volume ratio of bacterial suspension). Under the conditions that temperature was 30 ℃, pH was 6, inoculation amount was 10% (volume ratio), initial concentration of NP solutions was 20 mg/L, NP degradation rate by ZJF reached 73.82%, compared with any single strain of the three bacteria, NP degradation rate by ZJF increased more than 15% during 6 days. Bioremediation of nonylphenol-polluted the Yangtze River and the Ancient Canal water by ZJF ware simulated. After a 6-day incubation period, the degrading rate of nonylphenol in Ancient Canal water was close to 80%, and the degrading rate of nonylphenol in Yangtze River water was 72.84%.

Photocatalytic degradation of nonylphenol using co-extruded dual-layer hollow fibre membranes incorporated with a different ratio of TiO2/PVDF

A photocatalytic reactor based on novel dual-layer hollow fibre membranes with immobilized titanium dioxide (TiO2) nanoparticles was proposed in this study and tested for the degradation of highly recalcitrant endocrine disrupting compound of nonylphenol (NP). The presence of TiO2 on the outer surface of dual-layer hollow fibres was confirmed by scanning electron microscopy (SEM), energy dispersion of X-ray (EDAX), and atomic force microscopy (AFM). The effect of TiO2 loading, where the mass fraction TiO2/PVDF was varied from 0 to 1, on the degradation of toxic NP was evaluated by high-performance liquid chromatography (HPLC). The addition of TiO2 nanoparticles showed a significant effect on the membrane pore size and NP degradation rate. The presence of TiO2 on the outer layer of dual-layer hollow fibre membranes actively functioned as a photocatalyst, with the hollow fibre of TiO2/PVDF ratio of 1 possessed the highest NP degradation rate.

Impact of composting strategies on the degradation of nonylphenol in sewage sludge.

Nonylphenol can be present in sewage sludge, and this can limit the use of the sewage sludge to amend soil. Composting is one of the most efficient and economical methods of making sewage sludge stable and harmless. The nonylphenol degradation rates during composting with added bulking agents and with aeration applied were studied. Three organic bulking agents (sawdust, corn stalk, and mushroom residue) were added to sewage sludge, and the effects of the bulking agents used and the amount added on nonylphenol degradation were determined. The highest apparent nonylphenol degradation rate (71.6%) was found for sewage sludge containing 20% mushroom residue. The lowest apparent nonylphenol degradation rate (22.5%) was found for sewage sludge containing 20% sawdust. The temperature of the composting pile of sewage sludge containing 20% sawdust became too high for nonylphenol to be efficiently degraded, and the apparent nonylphenol degradation rate was lower than was found for sewage sludge containing 10% sawdust. Increasing the ventilating time from 5 to 15 min increased the apparent nonylphenol degradation rate from 19.7 to 41.6%. Using appropriate aerobic conditions facilitates the degradation of nonylphenol in sewage sludge, decreasing the risks posed by sewage sludge applied to land. Adding too much of a bulking agent can decrease the amount of the nonylphenol degraded. Increasing the ventilating time and the amount of air supplied can increase the amount of nonylphenol degraded even if doing so causes the composting pile temperature to remain low.

Biodegradation of toxic chemicals by Pleurotus eryngii in submerged fermentation and solid-state fermentation.

The toxic chemicals bisphenol A (BPA), bisphenol F (BPF), nonylphenol (NP), and tetrabromobisphenol A (TBBPA) are endocrine-disrupting chemicals that have consequently drawn much concern regarding their effect on the environment. The objectives of this study were to investigate the degradation of BPA, BPF, NP, and TBBPA by enzymes from Pleurotus eryngii in submerged fermentation (SmF) and solid-state fermentation (SSF), and also to assess the removal of toxic chemicals in spent mushroom compost (SMC). BPA and BPF were analyzed by high-performance liquid chromatography; NP and TBBPA were analyzed by gas chromatography. NP degradation was enhanced by adding CuSO4 (1 mM), MnSO4 (0.5 mM), gallic acid (1 mM), tartaric acid (20 mM), citric acid (20 mM), guaiacol (1 mM), or 2,2'-azino-bis- (3-ethylbenzothiazoline-6-sulfonic acid; 1 mM), with the last yielding a higher NP degradation rate than the other additives from SmF. The optimal conditions for enzyme activity from SSF were a sawdust/wheat bran ratio of 1:4 and a moisture content of 5 mL/g. The enzyme activities were higher with sawdust/wheat bran than with sawdust/rice bran. The optimal conditions for the extraction of enzyme from SMC required using sodium acetate buffer (pH 5.0, solid/solution ratio 1:5), and extraction over 3 hours. The removal rates of toxic chemicals by P. eryngii, in descending order of magnitude, were SSF > SmF > SMC. The removal rates were BPF > BPA > NP > TBBPA.

Fungal laccases degradation of endocrine disrupting compounds.

Over the past decades, water pollution by trace organic compounds (ng/L) has become one of the key environmental issues in developed countries. This is the case of the emerging contaminants called endocrine disrupting compounds (EDCs). EDCs are a new class of environmental pollutants able to mimic or antagonize the effects of endogenous hormones, and are recently drawing scientific and public attention. Their widespread presence in the environment solicits the need of their removal from the contaminated sites. One promising approach to face this challenge consists in the use of enzymatic systems able to react with these molecules. Among the possible enzymes, oxidative enzymes are attracting increasing attention because of their versatility, the possibility to produce them on large scale, and to modify their properties. In this study five different EDCs were treated with four different fungal laccases, also in the presence of both synthetic and natural mediators. Mediators significantly increased the efficiency of the enzymatic treatment, promoting the degradation of substrates recalcitrant to laccase oxidation. The laccase showing the best performances was chosen to further investigate its oxidative capabilities against micropollutant mixtures. Improvement of enzyme performances in nonylphenol degradation rate was achieved through immobilization on glass beads.

Isolation and Characterization of Nonylphenol-degrading Bacteria

To isolate a nonylphenol (NP)-degrading bacterium, we isolated a single colony from the NP-degrading microbial consortium SW-3, which was previously isolated from an aqueous environment. Ten colonies that exhibited different cell morphologies were isolated and the strains were named SW-3-A, -B, -C, -D, -E, -F1, -F2, -G, -H, and -I. The ability of isolates to degrade NP was evaluated by kinetic analysis by the constant of NP degradation rate (<TEX>$k_1$</TEX>) and the half-life time of NP degradation (<TEX>$t_{1/2}$</TEX>). SW-3-F1, -F2, -G, and -I strains were superior at degrading NP. The <TEX>$k_1$</TEX> and <TEX>$t_{1/2}$</TEX> values of the four strains were sixfold higher and one-sixth lower, respectively, than those of the consortium strain. Additionally, SW-3-F1, -G, and -I strains were tested for their ability to degrade NP during coculture. NP degradation by coculture with a combination of all three strains was inferior to that of culture conducted with single isolates, suggesting that the three strains are antagonistic toward each other during NP degradation.

Mechanism Study on Photodegradation of Nonylphenol in Water by Intermediate Products Analysis

The photodegradation mechanisms of nonylphenol (NP) with the involvement of dissolved oxygen (DO), hydro- gen peroxide, nitrate ion and chloride ion in water by simulated sunlight were studied, respectively. The influence of each factor on the photodegradation of NP has been assessed through contrasting the residual rate of NP. And the photodegrada- tion pathways in different conditions have been proposed according to the intermediate products identified by GC-MS. DO was a key factor in the photodegradation of NP and the rate of photoreaction depended on O2 concentration; the existence of H2O2 or 3 NO - increased the NP degradation rate significantly; with the existence of H2O2, the addition of Cl - first acceler- ated then slowed down the NP degradation rate. When NP reacted with DO, 4-nonylcatechol, nonanol, nonanal and nonoic acid have been identified as the degradation products. The accumulated amount of nonoic acid was the most. The proposed mechanism was that the 4-nonylcatechol and ortho-quinone derivative were produced after the formation of 4-nonylphenoxyl radical and superoxide radical anions 2 (O ) •- , then the intermediates underwent conjugate addition, nonanol, nonanal and nonoic acid were produced. In the presence of H2O2, 4-n-akylphenol (HOC6H4-CnH2n+1, n=2~8), 4-nonylcatechol, nonanol, nonanal and nonoic acid were the degradation products. And the accumulated amount of nonanal was the most. The hydroxyl radicals (•OH) generated by the photolysis of H2O2 attacked the electronic gathered positions of NP molecules. The products detected in the presence of 3 NO - were same as which detected in the presence of H2O2. The irradiated 3 NO - can produce •OH andNO2, so 2-nitryl-4-nonylphenol was found as the product ofNO2 attacking the ortho-position of phenolic hy- droxyl. In the presence of Cl - and H2O2, the nonanoyl chloride was found. The accumulated amount of nonanal was the most, so the probable mechanism was that the chlorine radical which generated from the reaction ofOH and Cl - reacted

Modeling of nonylphenol degradation by photo-nanocatalytic process via multivariate approach

Modeling of photocatalytic degradation of nonylphenol (NP), an endocrine disrupter and toxic compound, has been investigated in synthetic aqueous solutions containing ZnO nanoparticles as semiconductor using multivariate approach. In this regard, a full factorial experimental design was performed in order to study the main variables affecting the degradation process as well as their most significant interactions. Initial NP concentrations ([NP] 0) of 0.454–9.08 μM, were treated with UV–vis/ZnO using different pH and nanocatalyst loading rates. Effect of experimental parameters on the NP degradation rate constant was established by the response surface plots. The degradation rate constant decreased with an increase in the initial concentration of NP, while it increased with ZnO loading until a concentration of 0.5 g L −1. The rate constant increases with increase in pH up to 10, after which a significant decrease is observed. The results showed that most influential factors on NP degradation constant are the [NP] 0, pH of reaction media, and ZnO loading rate, and the most significant interaction is [NP]-pH. Finally, two mathematical models have been proposed to estimate NP degradation rate constant ( k) on the basis of the significant variables and interactions. Predicted results of models showed good agreement with the experimental data ( R 2 = 0.83 and 0.93).

Biodegradation of nonylphenol in soil

We investigated the effects of various factors (brij 30, brij 35, yeast extract, hydrogen peroxide and compost) on the aerobic degradation of nonylphenol (NP) in soil and characterized the structure of the microbial community in that soil. Residues of NP were measured using gas chromatography–mass spectrometry (GC–MS) and a change of microbial communities was demonstrated using denaturing gradient gel electrophoresis (DGGE). The results showed that Taichung sandy clay loam had higher NP degradation rate than Kaoshiung silty clay. The addition of compost, yeast extract (0.5 mg/l), brij 30 (55 μM), or brij 35 (91 μM) enhanced NP degradation, while the addition of hydrogen peroxide (1.0 mg/l) inhibited its degradation. We also found that the addition of various substrates changed the microbial community in the soils. Cytophaga sp. and Ochrobactrum sp. were constantly dominant bacteria under various conditions in the soil.

Anaerobic degradation of nonylphenol in sludge

We investigated the effects of various factors on the anaerobic degradation of nonylphenol (NP) in sludge. NP (5 mg/l) anaerobic degradation rate constants were 0.029 1/day for sewage sludge and 0.019 l/day for petrochemical sludge, and half-lives were 23.9 days and 36.5 days respectively. The optimal pH for NP degradation in sludge was 7 and the degradation rate was enhanced when the temperature was increased. The addition of yeast extract (5 mg/l) or surfactants such as brij 30 or brij 35 (55 or 91 μM) also enhanced the NP degradation rate. The addition of aluminum sulfate (200 mg/l) inhibited the NP degradation rate within 84 days of incubation. The high-to-low order of degradation rates was: sulfate-reducing conditions > methanogenic conditions > nitrate-reducing conditions. Sulfate-reducing bacteria, methanogen, and eubacteria are involved in the degradation of NP, sulfate-reducing bacteria being a major component of sludge.