Simultaneous Phenol Degradation Research Articles

Capacity of Marine Microalga Tetraselmis suecica to Biodegrade Phenols in Aqueous Media

Phenolic compounds are toxic and dangerous to the environment and human health. Although the removal of phenols and their derivatives is very difficult, it has been achieved by applying some biological processes. The capacity of microalga to remove phenolic compounds has been demonstrated; however, few reports of the removal of these compounds in a mixture have been published. The removal of phenol, p-cresol and o-cresol was performed by batch kinetics at 50 and 100 mg L−1, and the simultaneous degradation of phenol, p-cresol and o-cresol was carried out in a mixture at 40 mg L−1 using the marine microalga Tetraselmis suecica. The kinetic study was carried out for 192 h. For concentrations of 50 mg L−1 and 100 mg L−1, phenolic compound consumption efficiencies greater than 100% and 85%, respectively, were obtained, and up to 73.6% removal in the mixture. The results obtained indicate that the marine microalga carries out a process of the oxidation of organic matter and phenolic compounds, mineralizing up to 31.4% to CO2 in the mixture. Biological treatments using the marine microalga T. suecica can be considered feasible to treat effluents with concentrations similar to those of the present study.

Characteristics and mechanism of simultaneous nitrate and phenol removal by a newly isolated Cupriavidus oxalaticus T2

Phenol and nitrate in wastewater are harmful to organisms and the environment due to their ecotoxicity. Biological treatment is considered as an environmentally friendly approach for their removal. At present, limited studies explored the capability of single bacterium with simultaneous phenol degradation and aerobic denitrification. In this work, a Cupriavidus oxalaticus T2 with the capability of simultaneous phenol degradation and denitrification under aerobic conditions was isolated from activated sludge. Single factor tests demonstrated that the denitrification optimal conditions of T2 were the carbon source of sodium succinate, C/N ratio of 10, 30 °C, shaking speed of 150 rpm, and pH of 6–7. Strain T2 could remove 100 mg/L NO3−-N within 12 h under optimal conditions without obvious accumulation of NO2−-N and NH4+-N. Moreover, it could simultaneously remove 69 mg/L of NO3−-N and 1000 mg/L of phenol. This study revealed that the strain degraded phenol via ortho-pathway and removed nitrate involved in two pathways: denitrification and dissimilatory nitrate reduction to ammonium. A new strain with the capability of simultaneous nitrate removal and phenol degradation was characterized, suggesting its potential application in further eco-friendly treatment of wastewater.

Rapid cultivation of the aerobic granules for simultaneous phenol degradation and ammonium oxidation in a sequencing batch reactor

The rapid cultivation strategy of aerobic granular sludge (AGS) for simultaneous phenol degradation and ammonium oxidation was studied in a sequence batch reactor (SBR). The short-term inhibitory kinetics of phenol was studied through batch experiments. For the sodium acetate fed AGS, the phenol inhibition constants (Ki) of specific oxygen utilization rate by heterotrophic bacteria (SOURh) was 508.6 mg/L. The Ki of specific ammonium utilization rate (SAUR) was 232.3 mg/L. After 28 days’ acclimatization, the phenol and NH4+-N removal rates of the SBR reached 94.0% and 96.4% when the influent phenol and NH4+-N concentrations were 1000 and 33.5 mg/L, respectively. The phenol removal loading rate was 1.69 kg/(m3·d). For the mature phenol&ammonium degrading AGS, the polysaccharide (PS) and protein (PN) concentrations were 247.4 ± 10.3 and 68.6 ± 6.5 mg/g VSS, respectively. The functional groups analysis showed that the amount of OH, NH, CO and CC groups remained unchanged in the mature phenol&ammonium degrading AGS.

The Effect of Crystalline Phase on the Simultaneous Degradation of Phenol and Reduction of Chromium (VI) Using UV/TiO 2 Photocatalysis

Chromium (IV) contamination in industrial wastewater has been on the rise due to increased anthropogenic activities. Similarly, typical industrial wastewater contains high levels of phenol as a result of the direct disposal on phenol into industrial effluent or as degradation products from phenolic compounds. Both these contaminants have adverse effects to human health and the environment and it is therefore necessary to develop technologies to remove them in a sustainable manner. Photocatalysis using TiO2 catalyst activated by UV light is one such technology as it can either oxidize and mineralize organic pollutants or reduce heavy metals contaminants into a noble form. Degussa P25 TiO2 is normally used in photocatalysis due its ability to reduce electron-hole recombination. It has been theorized that the addition of organic compounds as hole scavengers during the photocatalytic reduction of Cr(VI) aids in the reduction efficiency. This study investigated the use of anatase-form TiO2 on the reduction of Cr(VI) in the presence of phenol and compared the results to similar work carried out by our group out Degussa P25 as catalyst. The anatase was shown to be an effective catalyst in the reduction of Cr(VI) with as much as 32 % reduction occurring at neutral pH with no phenol present. Adjusting the solution pH to 3 increased the percentage reduction to 40.7 % whilst addition of 100 ppm of phenol at pH 3 resulted in a 52.3 % Cr(VI) reduction. Comparison of the results obtained for anatase and Degussa P25 TiO2 at the same pH revealed approximately the same Cr(VI) reduction efficiencies with the Degussa P25 having a slight edge. This suggests that the nature of the crystal phase of the two TiO2 investigated does not significantly influence the reduction efficiency of Cr(VI) in the presence of phenol.

Reduction of selenite to elemental Se(0) with simultaneous degradation of phenol by co-cultures of Phanerochaete chrysosporium and Delftia lacustris.

The simultaneous removal of phenol and selenite from synthetic wastewater was investigated by adopting two different co-culturing techniques using the fungus Phanerochaete chrysosporium and the bacterium Delftia lacustris. Separately grown biomass of the fungus and the bacterium (suspended co-culture) was incubated with different concentrations of phenol (0-1,200 mg/L) and selenite (10 mg/L). The selenite ions were biologically reduced to extracellular Se(0) nanoparticles (3.58 nm diameter) with the simultaneous degradation of up to 800 mg/L of phenol. Upon growing the fungus and the bacterium together using an attached growth co-culture, the bacterium grew as a biofilm onto the fungus. The extracellularly produced Se(0) in the attached growth co-culture had a minimum diameter of 58.5 nm. This co-culture was able to degrade completely 50 mg/L phenol, but was completely inhibited at a phenol concentration of 200 mg/L.

Simultaneous degradation of phenol and paracetamol using carbon/MWCNT/Fe3O4 composite nanofibers during photo-like-Fenton process

In the present study, the carbon/MWCNT/Fe3O4 composite nanofibers were prepared by electrospinning process and their application was investigated for simultaneous degradation of phenol and paracetamol through the photo-like-Fenton process. The prepared nanofibers were characterized using SEM and XRD analysis. The Box–Behnken design was used to evaluate the relation between the photo-like-Fenton operating variables including pH (3–5), initial concentrations of phenol and paracetamol (50–250 mg/L), H2O2 concentration (5–25 mmol/L), reaction time (5–25 min), temperature (35–55°C) and carbon/MWCNT/Fe3O4 nanofiber dosage (0.05–0.10 g/L) on the phenol and paracetamol removing. The experimental design results showed that the experimental maximum phenol and paracetamol degradation efficiencies were found to be 99.9% and 99.0% at pH of 3.4, phenol and paracetamol concentrations of 50 mg/L, H2O2 concentration of 15 mmol/L, reaction time of 25 min, temperature of 45°C and nanofiber dosage of 0.075 g/L. The prepared carbon/MWCNT/Fe3O4 nanofiber were successfully reused for five times after regeneration. The obtained results revealed the high potential of carbon/MWCNT/Fe3O4 composite nanofibers for a short-time mineralization of phenolic compounds from wastewater during photo-like-Fenton process.

Simultaneous degradation of phenol and paracetamol during photo-Fenton process: Design and optimization

In the present study, the photo-Fenton process was applied for the treatment of phenol and paracetamol in a binary system. The cobalt ferrite nanoparticles synthesized by microwave heating method were applied during photo-Fenton process. The nanoparticles were characterized by XRD and SEM analysis. The response surface methodology based on Box–Behnken design was used to evaluate and optimize the interactive effects of five operating variables including pH, initial concentrations of phenol and paracetamol, H2O2 concentration and cobalt nanoferrite dosage on the phenol and paracetamol degradation rates in photo-Fenton process. The results of experimental design indicated that the pH of 3.5, H2O2 concentration of 50mmol/L and cobalt nanoferrite dosage of 0.2g/L maximize the efficiency of phenol and paracetamol degradation rates at the time in photo-Fenton process. The maximum experimental phenol and paracetamol degradation efficiencies for initial concentrations of 20mg/L of phenol and paracetamol were found to be 95 and 85%, respectively. These values were in good agreement with the estimated values by the model in optimum conditions (94.5 and 84.4% for phenol and paracetamol degradation efficiencies). The obtained results demonstrated an excellent ability of synthesized cobalt ferrite nanoparticles to remove the phenolic compounds in photo-Fenton process.

Cometabolic degradation of para-nitrophenol and phenol by Ralstonia eutropha in a Kissiris-immobilized cell bioreactor

Ralstonia eutropha was able to degrade p-nitrophenol (PNP) at concentrations ranging from 5 to 15mg l−1 in the presence of phenol which was kept at the constant concentration of 200 mg l−1. More than 90% of phenol was degraded within 30 h and in the absence of PNP. While in this time period and in the presence of 15 mg l−1 less than 30% of phenol was degraded and PNP removal ability of the test bacterium was about 20%. Kissiris as a natural source of silicon dioxide having a very rigid structure with many micropores irregularly distributed throughout its surface was used to evaluate effectiveness of the cell immobilization using a Kissiris-immobilized cell bioreactor [ICB]. By applying phenol-feeding regime in the ICB operated in a batch recycling mode, simultaneous degradation of phenol in total amount of 1,000 mg l−1 with 15 mg l−1 PNP was achieved within 40 h.

Simultaneous degradation of phenol and n-hexadecane by Acinetobacter strains

Three phenol- and alkanes-degrading bacterial strains were isolated from a freshwater sample. Upon the 16S rRNA gene analysis, phenotype and physiological features, the three strains were designated as Acinetobacter sp. with both phenol hydroxylase gene (phe) and alkane monooxygenase gene (alkM) detected. They could simultaneously degrade phenol and n-hexadecane for growth, but prefer phenol than n-hexadecane. Between phenol (400mgl−1) and n-hexadecane (400mgl−1), n-hexadecane enhanced phenol degradation in mineral salt medium (MSM), while phenol affects negatively the n-hexadecane degradation. However, combination of phenol (400mgl−1) and n-hexadecane (400mgl−1) in MSM led to higher growth of the strains than the phenol and n-hexadecane separately. The transcription levels of phe and alkM genes supported the physiological properties of the strains.

Simultaneous degradation of phenol and 3-chlorobenzoate by a mixture of separately immobilized cells of two strainsof Pseudomonas – A preliminary study

Simultaneous degradation of halogenated and non-halogenated aromatic compounds that are catabolised through different cleavage pathways is generally difficult due to biochemical incompatibility. However, free cells of a mixed culture of Pseudomonas sp. CP4 that degrades phenol through meta-pathway and Pseudomonas aeruginosa strain 3mT that degrades 3-chlorobenzoate through ortho-pathway was shown, earlier, to degrade mixtures of phenol/cresols and 3-chlorobenzoate in shake flasks. In the present study the degrading efficiency of these strains when immobilized (separately) in Ca-alginate gel beads was tested using a fluidized bed reactor. Complete mineralization of up to 5 mM equimolar mixture of phenol and 3-chlorobenzoate was observed when the beads were used at 1:1 ratio. From a 10 mM equimolar mixture although phenol was completely mineralized 3-chlorobenzoate degradation was not complete as evidenced by accumulation of some intermediary metabolites and the release of only 86% of inorganic chloride (Cl ¯ ). Degradation rates of both the compounds by the immobilized cells, in general, were far better than that by the free cells. With further studies to select suitable gel matrices and optimization of bioreactor conditions these strains can be effectively deployed for treatment of heterogeneous aromatic wastes.

Bismuth‐Doped Ordered Mesoporous TiO2: Visible‐Light Catalyst for Simultaneous Degradation of Phenol and Chromium

A controllable and reproducible synthesis of highly ordered two-dimensional hexagonal mesoporous, crystalline bismuth-doped TiO(2) nanocomposites with variable Bi ratios is reported here. Analyses by transmission electron microscopy, X-ray diffraction, Raman, and X-ray photoelectron spectroscopy reveal that the well-ordered mesostructure is doped with Bi, which exists as Bi(3+) and Bi((3+x+)). The Bi-doped mesoporous TiO(2) (ms-TiO(2)) samples exhibit improved photocatalytic activities for simultaneous phenol oxidation and chromium reduction in aqueous suspension under visible and UV light over the pure ms-TiO(2), P-25, and conventional Bi-doped titania. The high catalytic activity is due to both the unique structural characteristics and the Bi doping. This new material extends the spectral response from UV to the visible region, and reduces electron-hole recombination, which renders the 2.0% Bi-doped ms-TiO(2) photocatalyst highly responsive to visible light.

Simultaneous Phenol Degradation and Chromium(VI) Reduction in an Anaerobic Fixed-Biofilm Process

Simultaneous Phenol Degradation and Chromium(VI) Reduction in an Anaerobic Fixed-Biofilm Process

Simultaneous chromium reduction and phenol degradation in a coculture of Escherichia coli ATCC 33456 and Pseudomonas putida DMP-1.

In a defined coculture of a Cr(VI) reducer, Escherichia coli ATCC 33456, and a phenol degrader, Pseudomonas putida DMP-1, simultaneous reduction of Cr(VI) and degradation of phenol was observed. When Cr(VI) was present in the coculture, quantitative transformation of Cr(VI) into Cr(III) proceeded with simultaneous degradation of phenol. Cr(VI) reduction was correlated to phenol degradation in the coculture as demonstrated by a regression analysis of the cumulative Cr(VI) reduction and the cumulative phenol degradation. Both the rate and extent of Cr(VI) reduction and phenol degradation were significantly influenced by the population composition of the coculture. Although Cr(VI) reduction occurred as a result of E. coli metabolism, the rate of phenol degradation by P. putida may become a rate-limiting factor for Cr(VI) reduction at a low population ratio of P. putida to E. coli. Phenol degradation by P. putida was very susceptible to the presence of Cr(VI), whereas Cr(VI) reduction by E. coli was significantly influenced by phenol only when phenol was present at high concentrations (> 9 mM).

Plasmid-coded degradation of salicylate using the catechol cleavage pathway of the host

Degradation rates of salicylate and phenol by Pseudomonas putida PpG1064 carrying the nahG gene on a multicopy plasmid were compared with those in NAH-carrying P. putida. Degradation rates of salicylate and phenol and the growth rate of the recombinant were higher than those in NAH-carrying P. putida in SP medium. The catechol 1,2 oxygenase activity of the recombinant in Sp medium was about twice that of the catechol 2,3 oxygenase and catechol 1,2 oxygenase activities of NAH-carrying P. putida. It was suggested that in simultaneous degradation of phenol and salicylate, the recombinant stimulated its ortho cleavage pathway and attained the higher degradation rates and growth rate.