Degradation Of Nonionic Surfactants Research Articles

Impact of various factors on the kinetics of non-enzymatic fragmentation of a monoclonal antibody

Non-enzymatic hinge fragmentation of monoclonal antibodies (mAb) is considered a critical quality attribute since it changes the primary sequence of the proteins, thereby leading to structural changes which can affect stability, function, and efficacy. While peptide bonds are exceptionally stable under physiological conditions, reactive side chains of a few residues, the flexibility of the backbone, and physicochemical parameters such as pH, temperature, and the reaction of radicals and metal ions can promote the cleavage of peptide bonds. In this study, the relative extent and rate of fragmentation are compared with respect to the presence of several different factors (including hydrogen peroxide, metal ion, and temperature) as measured by size exclusion chromatography. A kinetic model of monomer degradation as a function of time (mAb only) is created. In the presence of either H2O2 or Cu2+, or both, the reaction kinetics follow different orders depending on the reaction conditions. The half-life for peptide bond cleavage of the mAb hinge region was 385 days at 40 °C and decreases to 250, 48, and 45 days in the presence of H2O2, Cu2+, and a combination of H2O2 and Cu2+, respectively. A temperature dependence of peptide bond cleavage at 35 °C, 40 °C, 45 °C, and 50 °C showed Arrhenius behavior with an apparent activation energy of 76.9 ± 16.4 kJ/mol. The reaction rates obtained from the Arrhenius equation were then extrapolated to predict fragmentation rates under real storage conditions (e.g., at 2–8 °C). We demonstrate that trace levels of impurities including peroxide left after surface sterilization or degradation of non-ionic surfactants or metal ions from the buffer components can significantly affect the stability of a mAb.

UV-light photocatalytic degradation of non-ionic surfactants using ZnO nanoparticles

The aim of this study was to evaluate the performance of zinc oxide nanoparticles as a photocatalyst for photodegradation of two model non-ionic surfactants (Triton X-100 and C12E10). The first part of the investigation was focused on the synthesis and characterization of ZnO nanoparticles, since its crystalline structure strongly impacts its photocatalytic properties. Based on the results of the XRD analysis, it was concluded that the obtained material occurred in the form of hexagonal wurtzite with a polycrystalline structure. FT-IR and XPS analyses were used to elucidate and confirm the nanomaterial structure, whereas investigation of N2 adsorption/desorption and SEM/TEM imaging allowed to establish that the synthesized ZnO was characterized as a mesoporous material with uniform, spherical shape and particle size fluctuating between 90 and 130 nm. The second part of the study included spectrophotometric assessment of the photodegradation process. The use of the obtained ZnO nanoparticles allowed to achieve efficient photodegradation of both C12E10 (92%) and Triton X-100 (82%) after 1 h of UV irradiation. The Langmuir–Hinshelwood mechanism was used to describe the reaction kinetics. Subsequent LC-MS/MS analysis of the residues indicated that the degradation mechanism is most likely based on both central fission of the surfactant molecules with further terminal oxidation of poly(ethylene glycol) and terminal oxidation leading to carboxylic derivatives of surfactants.

Influence of Sucrose on the Diversity of Bacteria Involved in Nonionic Surfactant Degradation in Fluidized Bed Reactor

The microbial diversity from a fluidized bed reactor (FBR) for nonionic surfactant linear alcohol ethoxylate (LAE – Genapol® C100) degradation was determined by 454-pyrosequencing analysis. The FBR was operated with a hydraulic retention time of 18 h for 163 days and fed with synthetic substrate supplemented with yeast extract and LAE. The system was operated in two stages: (I) 80 mg/L of sucrose in synthetic substrate plus 107.4 ± 47.3 mg/L LAE and (II) synthetic substrate without sucrose and 97.9 ± 37.7 mg/L of LAE. By using 454 pyrosequencing, 14,325 sequences with an average length of 225 bp were generated. Proteobacteria phyla predominated in support material (sand) biofilm, while for the biomass from the phase separator, there was a prevalence of Acidobacteria phyla. Furthermore, many reads were related to genera of degraders of LAE and other nonionic surfactants (Desulfosporomusa, Syntrophomonas, Desulfobulbus, Geobacter, Dongia, etc.). Higher diversity and equitability indices were obtained for the biomass from the phase separator. The use of sucrose (C12H22O11) as co-substrate for LAE degradation favored the microbial diversity in the support material and in the phase separator, indicated by the Shannon-Wiener (H′) index. The removal of sucrose from the synthetic substrate definitely altered the microbial community but did not influence the LAE efficiency removal.

Drag reduction and degradation of nonionic surfactant solutions with organic acid in turbulent pipe flow

We investigated the drag reduction and degradation of nonionic surfactant (Aromox) solutions, which mainly consisted of oleyldimethylamine oxide (ODMAO) and had non-toxic and biodegradable properties, by measuring the pressure drop and flow rate in the circuit pipe flow system using a pump. It is revealed that the addition of a small amount of organic acids such as salicylic and cuminic acids to nonionic surfactant solutions noticeably improves mainly two kinds of drag-reducing abilities. The first is the increase in the critical Reynolds number at which the drag reduction ratio is the maximum, i.e., the drag reduction can be obtained at the larger Reynolds number. The second is the decrease in the level of degradation caused by the continuous circulation of surfactant solutions in the closed pipe system, so that the high level of the drag reduction keeps for a long time. Comparing with the mixture of typical cationic surfactant (Ethoquad O/12) which consists of the oleyl-bis-hydroxyethyl-methyl-ammonium chloride (OBHEMA) and sodium salicylate as a counterion in practical use, the mixture of nonionic solution and salicylic acid proposed in this study shows the comparable or better drag-reducing ability at the same concentration and temperature of surfactant solutions.

Heterogeneous Photocatalytic Degradation of Triton X-100 in Aqueous TiO2 Suspensions

The increasing utilization of surfactants generates a great amount of wastes. Surfactants and their more toxic degradation by-products in the environment affect the biota greatly. In particular, the low biodegradation of nonionic surfactants requires efficient oxidation treatments. In addition, the extracted contaminants by high concentrations of non-ionic surfactants in soil remediation may be completely treated using advanced oxidation process and thus the degradation of non-ionic surfactants needs to be checked in this case. The photocatalytic degradation of Triton X-100, a non-ionic surfactant, in aqueous titania suspensions was investigated as a function of catalyst dosage, pH, addition of hydrogen peroxide, potassium persulfate, and Tert-butyl alcohol. For the treatment of 20 mg/L Triton X-100 solutions, the optimum catalyst dosage and pH were determined to be 1 g/L and 6, respectively. The degradation efficiency of Triton X-100 by potassium persulfate was higher than that by hydrogen peroxide when the same mol of oxidants were used. Tert-butyl alcohol can strongly inhibit the photocatalytic oxidation reactions of Triton X-100. The degradation rates as a function of initial surfactant concentrations were interpreted by using a Langmuir-Hinshelwood model. With 0.2 g/L titania or even an additional 0.1 g/L hydrogen peroxide to completely degrade 1 mg/L phenanthrene in a 2 g/L Triton X-100 solution within 30 min, in this case the degradation efficiency of Triton X-100 was less than 5%. This proved that the strategy that surfactants were used as solubilizing agents for the removal of contaminants from soils followed by heterogeneous photocatalytic degradation was feasible.Within 120 min, 2 g/L of Triton X-100 can be degraded up to 67% by the addition of both 1 g/L titania and 1 g/L hydrogen peroxide. Under the right conditions, Triton X-100 can be completely degraded.

Nonylphenol Polyethoxylates Degraded by Three Different Wavelengths of UV and Their Genotoxic Change—Detected by Generation of γ‐H2AX

UV rays in sunlight are an important factor in the degradation of chemicals. In this study, we investigated the degradation of nonionic surfactants, nonylphenol polyethoxylates (NPEOs) with 10 or 70 ethylene oxide (EO) units using UVA, B and C, and their genotoxic change based on phosphorylation of histone H2AX (γ-H2AX), a marker of DNA damage. NPEOs were degraded dependent on the energy of UV, that is, UVC having the highest energy was most effective, whereas UVA having the lowest energy caused little change. The EO side chain of NPEO(70) was broken near the benzene ring by UV, producing NPEOs with a shortened EO chain (around 10 units). The generation of γ-H2AX reflected the pattern of degradation; shortening of the EO chain changed NPEO(70) into an inducer for γ-H2AX, and degradation of NPEO(10) attenuated the genotoxicity. The γ-H2AX generated by NPEO(10) and UV-degraded NPEO(70) was independent of the cell cycle. The formation of DNA double strand breaks detected by gel electrophoresis was consistent with the results for γ-H2AX. These results suggested that UV rays can make NPEOs harmless or genotoxic according to the degradation of the EO side chain, the effects being dependent on wavelength.

Photo-Fenton degradation of non-ionic surfactant and its mixture with cationic or anionic surfactant

The oxidative degradation of non-ionic surfactants by the photo-Fenton process has been examined. The photo-Fenton degradation kinetics of mixtures of non-ionic surfactant and other type surfactants has been also investigated since mixtures of non-ionic and ionic surfactants are commonly used to utilize their synergistic effects in many practices. Effects of operating parameters such as dosages of Fenton reagents (iron and hydrogen peroxide) and UV light intensity on the degradation of commercial non-ionic surfactant Sannonic SS-90 (polyoxyethylene alkyl ether) were studied. Although the dosages of the Fenton reagents increased the degradation rate up to the optimum dosages, further addition of the reagents could not enhance the degradation rate. Excess dosages of Fe and H2O2 caused excess OH radicals which could be a scavenger of OH radicals and as a result could not enhance the degradation of the surfactant. The increase in UV light intensity resulting in the faster photo-Fenton process or the enhancement of OH radical formation rate led to the increase in degradation rate of non-ionic surfactant. Although the existence of the anionic surfactant (sodium dodecylbenzene sulphonate) would inhibit the degradation of the non-ionic surfactant due to the formation of complex with Fe ion, the existence of cationic surfactant (dodecyltrimethyl ammonium chloride) affected insignificantly the photo-Fenton degradation process of the non-ionic surfactant.

Isolation from Tannery Wastewater and Characterization of Bacterial Strain Involved in Nonionic Surfactant Degradation

A bacterial strain OPQa3 capable of utilizing nonylphenol polyoxyethylene (NPnEO) as sole carbon source was isolated from water samples collected from tannery waste treatment plant suffered long-time application of NPnEO by enrichment method. It was preliminarily identified as Brevundimonas sp. (most similar to Brevundimonas diminuta (EU434566.1)), according to the observation of morphological characteristics, physiological-biochemical tests and the similarity analysis of its 16S rDNA gene sequence. Inoculated 2% of OPQa3 suspension, to give a final OD600of approximately 0.70, to inorganic salt medium in which the initial concentration of NPnEO was 746 mg•L-1, degradation test showed that, the degradation rate of strain OPQa3 was 84.5% within 120 hours, the optimum temperature was 30°C while the optimum pH value was about 7, and the growth period was of 24 hours.

Photocatalytic degradation of nonionic surfactant, Brij 35 in aqueous TiO 2 suspensions

The photocatalytic oxidation of nonionic surfactant, Brij 35 in aqueous TiO 2 suspensions was investigated as a function of catalysts loading, light intensity ( I), initial Brij 35 concentration [Brij] 0, dissolved oxygen concentration [ p O 2 ], and pH. A monolithic swirl-flow photoreactor was used that allowed to perform a systematic analysis of rates at various loadings of TiO 2 in order to distinguish “kinetic” and “transport” limited regimes for the photocatalytic degradation of Brij 35 in TiO 2 suspensions. The optimal catalyst loading was determined to be 0.1 g L −1 TiO 2 at a neutral pH. The true kinetic dependences of the photocatalytic degradation on I and [Brij] 0 were determined. A small increase in oxidation rate was observed with an increase in the partial pressure of the oxygen [ p O 2 ] in the system. The rates as a function of [Brij] 0 and [ p O 2 ] were interpreted using a Langmuir–Hinshelwood model. The complete photocatalytic degradation of Brij 35 was obtained in acidic to basic pH range, however, the removal of Brij 35 removal and subsequent decrease in TOC levels were more efficient at a neutral pH than acidic or basic pH.

Environmental fate of phenolic endocrine disruptors: field and laboratory studies

Alkylphenolic compounds derived from microbial degradation of non-ionic surfactants became a major focus of environmental research in the early 1980s. More toxic than the parent compounds and weakly oestrogenic, certain metabolites of nonylphenol polyethoxylate (NPnEO) surfactants, especially nonylphenol (NP), raised sustained concern over the risk they pose to the environment and triggered legal measures as well as partly voluntary actions by the manufacturing industry. Continuous progress in the development of analytical techniques is crucial to understand how these alkylphenolic compounds behave in wastewater treatment, the aquatic environment and in laboratory experiments. Measured concentrations and mass flows of phenolic endocrine disruptors, particularly nonylphenolic compounds, bisphenol A and parabens in municipal wastewater effluents and in the Glatt River, Switzerland, show that rain events leading to discharges of untreated wastewater into rivers have a great impact on the riverine mass flows of contaminants. Biotransformation experiments in our laboratory with nonylphenoxyacetic acid and individual NP isomers enabled the elucidation of degradation pathways of these compounds. The finding that nonylphenoxyacetic acid is metabolized via NP further underscores the role of NP as the most relevant metabolite in the degradation of NPnEO. Several Sphingomonadaceae bacterial strains were found to degrade alpha-quaternary 4-NP isomers by an ipso-substitution mechanism, and to use only the aromatic part of the molecule. These reactions turned out to be isomer specific, meaning that rate and extent of transformation depend on constitution, and possibly also on the absolute configuration of the alkyl side chain of a specific isomer. The observation that NP isomers with distinct oestrogenic activities are differentially degraded has significant implications for risk assessment.

Fate of Sulfamethoxazole, 4-Nonylphenol, and 17β-Estradiol in Groundwater Contaminated by Wastewater Treatment Plant Effluent

Organic wastewater contaminants (OWCs) were measured in samples collected from monitoring wells located along a 4.5-km transect of a plume of groundwater contaminated by 60 years of continuous rapid infiltration disposal of wastewater treatment plant effluent. Fifteen percent of the 212 OWCs analyzed were detected, including the antibiotic sulfamethoxazole (SX), the nonionic surfactant degradation product 4-nonylphenol (NP), the solvent tetrachloroethene (PCE), and the disinfectant 1,4-dichlorobenzene (DCB). Comparison of the 2005 sampling results to data collected from the same wells in 1985 indicates that PCE and DCB are transported more rapidly in the aquiferthan NP, consistent with predictions based on compound hydrophobicity. Natural gradient in situ tracer experiments were conducted to evaluate the subsurface behavior of SX, NP, and the female sex hormone 17beta-estradiol (E2) in two oxic zones in the aquifer: (1) a downgradient transition zone at the interface between the contamination plume and the overlying uncontaminated groundwater and (2) a contaminated zone located beneath the infiltration beds, which have not been loaded for 10 years. In both zones, breakthrough curves for the conservative tracer bromide (Br-) and SX were nearly coincident, whereas NP and E2 were retarded relative to Br- and showed mass loss. Retardation was greater in the contaminated zone than in the transition zone. Attenuation of NP and E2 in the aquifer was attributed to biotransformation, and oxic laboratory microcosm experiments using sediments from the transition and contaminated zones show that uniform-ring-labeled 14C 4-normal-NP was biodegraded more rapidly 130-60% recovered as 14CO2 in 13 days) than 4-14C E2 (20-90% recovered as 14CO2 in 54 days). There was little difference in mineralization potential between sites.

Effects of reaction conditions on nuclear laundry water treatment in Fenton process

This study presents the efficiency of Fenton process in the degradation of organic compounds of nuclear laundry water. The influence of Fe 2+ and hydrogen peroxide ratio, hydrogen peroxide dose, pH and treatment time were investigated. The degradation of non-ionic surfactant and other organic compounds was analysed as COD, TOC and molecular weight distribution (MWD). The most cost-effective degradation conditions were at H 2O 2/Fe 2+ stoichiometric molar ratio of 2 with 5 min mixing and H 2O 2 dose of 1000 mg l −1. With the initial pH of 6, the reductions of COD and TOC were 85% and 69%, respectively. However, the removal of the organic compounds was mainly carried out by Fenton-based Fe 3+ coagulation rather than Fenton oxidation. Fenton process proved to be much more efficient than previously performed ozone-based oxidation processes.

Ozonation for the Degradation of Organic Compounds from Nuclear Laundry Water

In this study, the efficiency of ozone to degrade organic compounds of nuclear laundry water was studied at different pH and temperatures and at elevated temperature with hydrogen peroxide. The degradation of non-ionic surfactant and other organic compounds was analyzed by COD, TOC, BOD and molecular weight distribution measurements. Zeta potential measurements were also performed in order to interpret the obtained results. The most favorable degradation conditions were at pH 7 with 43%, 34% and 61% reductions of COD, TOC and BOD, respectively.

Oxidative degradation of non-ionic surfactant (TritonX-100) by chromium(VI)

Degradation of polyoxyethylene chain of non-ionic surfactant (TritonX-100) by chromium(VI) has been studied spectrophotometrically under different experimental conditions. The reaction rate bears a first-order dependence on the [Cr(VI)] under pseudo-first-order conditions, [TritonX-100] ≫ [Cr(VI)] in presence of 1.16 mol dm −3 perchloric acid. The observed rate constant ( k obs) was 3.3 × 10 −4 to 3.5 × 10 −4 s −1 and the half-life ( t 1/2) was 33–35 min for chromium(VI). The effects of total [TritonX-100] and [H +] on the reaction rate were determined. Reducing nature of non-ionic TritonX-100 surfactant is found to be due to the presence of –OH group in the polyoxyethylene chain. It was observed that monomeric and non-ionic micelles of TritonX-100 were oxidized by chromium(VI). When [TritonX-100] was less than its critical micelle concentration (cmc) the k obs values increased from 0.76 × 10 −4 to 1.5 × 10 −4 s −1. As the [TritonX-100] was greater than the cmc, the k obs values increases from 2.1 × 10 −4 to 8.2 × 10 −4 s −1 in presence of constant [HClO 4] (1.16 mol dm −3) at 40 °C. A comparison was made of the oxidative degradation rates of TritonX-100 with different metal ion oxidants. The order of the effectiveness of different oxidants was as follows: permanganate > diperiodatoargentate(III) > chromium(VI) > cerium(IV).

OZONE-BASED ADVANCED OXIDATION PROCESSES IN NUCLEAR LAUNDRY WATER TREATMENT

The efficiency of ozone treatment in the degradation of organic compounds of nuclear laundry water is presented. Ozonation experiments were performed in different combinations of pH, hydrogen peroxide and ultraviolet radiation. The degradation of non-ionic surfactant and other organic compounds was analysed by chemical oxygen demand, total organic carbon, biochemical oxygen demand and the molecular weight distribution measurements. The optimal degradation circumstances were found to be at pH 7 with ozone, UV radiation and hydrogen peroxide addition. The transfer of ozone increased substantially thus resulting in decreased treatment time compared to our previous experiments. The reductions of chemical oxygen demand, total organic carbon and biochemical oxygen demand were about 46%, 32% and 70%, respectively.

Determination of Hormones and Non-ionic Surfactant Degradation Products in Small-Volume Aqueous Samples from Soil Columns Using LC-ESI-MS-MS and GC-MS

The leaching of two estrogens, 17β-estradiol and estrone, and two degradation products of non-ionic surfactants, octylphenol and nonylphenol, through a soil column were studied to estimate their transport behavior. Different concentration methods (lyophilization, solid phase extraction, and liquid–liquid extraction) were evaluated for analyzing these compounds in small effluent fractions (30–50 mL) collected. Liquid chromatography-mass spectrometry (LC-MS-MS) and gas chromatography-mass spectrometry (GC-MS) were employed for quantitative analysis of these compounds. After comparison, the lyophilization-LC-MS-MS method was found to be best suited for the analysis of the two estrogen hormones and the liquid–liquid extraction-GC-MS method best for the analysis of the two phenols in small samples in the soil column study. Because of their high sorption capacity, these compounds were mostly sorbed in the upper part of the soil column and were difficult to detect in column effluent.

Photocatalytic Degradation of Nonionic Surfactants with Immobilized TiO2 in an Airlift Reactor

The photocatalytic degradation of a nonionic surfactant, Sanonic SS-90 (polyoxyethylene alkyl ether) which is one of polyoxyethylene nonionic surfactants, in water has been investigated using immobilized titanium dioxide (TiO2) photocatalyst. An external UV irradiation type airlift reactor was used as a photoreactor. The effects of initial nonionic surfactant concentration, intensity of UV light, and concentrations of TiO2 photocatalyst on degradation rate of Sanonic SS-90 were examined. The photocatalytic decomposition of Sanonic SS-90 was assumed to be approximately described by the Langmuir–Hinshelwood kinetics. The rate constant of photocatalytic degradation was found to be proportional to TiO2 surface area and the square root of UV light intensity and independent on the initial concentration of Sanonic SS-90. The evaluated average UV light intensity in the airlift photoreactor was used to determine the rate constants in the Langmuir–Hinshelwood kinetics. It was found that the kinetic model for the degradation by immobilized TiO2 photocatalyst can simulate the experimental results reasonably.

Photocatalytic Degradation of Nonionic Surfactants with Immobilized TiO2 in an Airlift Reactor

Photocatalytic Degradation of Nonionic Surfactants with Immobilized TiO2 in an Airlift Reactor

Oxidative Degradation of Nonionic Surfactants with TiO2 Photocatalyst in a Bubble Column Reactor

AbstractThe photocatalytic reaction for oxidative degradation of a nonionic surfactant, Tween 80 (polyoxyethylene sorbitan monooleate), was examined using TiO2 photocatalyst powders. An external UV irradiation type slurry bubble column was used as a photoreactor. The rate constant of degradation was proportional to TiO2 surface area and the square root of UV light intensity and independent on the initial concentration of Tween 80. A simple model for intensity distribution profiles of UV light supplied to the liquid in the photoreactor was developed to use in determining the degradation rate constant. The proposed model could simulate the experimental results satisfactorily.

Degradation of 4-Nonylphenol in Homogeneous and Nonhomogeneous Mixtures of Soil and Sewage Sludge

Sewage sludge is frequently applied as fertilizers to cultivated land. However, municipal sewage sludge often contains organic contaminants including nonylphenol (NP), an intermediate from nonionic surfactant degradation. Knowledge about NP degradation in sludge-amended soil is an important prerequisite for adequate risk assessments. In this study, mineralization of 14C-labeled NP in homogenized and nonhomogenized sludge-soil mixtures was investigated. NP was degraded within 38 days in aerobic homogenized mixtures. In nonhomogeneous mixtures containing sludge aggregates, the degradation of NP was retarded and was generally not completed within 3 months (119-126 days). No detectable amounts of NP were transported from the sludge aggregates to the surrounding soil (detection limit: <0.04 mg of NP/kg dw of soil). Oxygen penetration into sludge aggregates was monitored for 50 days with an oxygen microelectrode. An extrapolation of the oxygen data suggested that more than 1 year was required to obtain fully aerobic conditions in a 2-cm sludge aggregate. Since NP is considered persistent in the absence of oxygen, residual amounts of NP may be present in the anaerobic center of aggregates for prolonged periods. The results demonstrate that sludge aggregate size and thus oxygen availability will be a major controlling factor for NP degradation in soil amended with sewage sludge and that the mobility of NP from sludge aggregates to the surrounding soil is negligible.