PVA-alginate Beads Research Articles

Eco-friendly Biodegradation of Hydrocarbons Compounds from Crude Oily Wastewater Using PVA/Alginate/Clay Composite Hydrogels

Immobilized microorganisms especially bacteria are most used rather than free cells to be protected from the environmental conditions when being used for the bioremediation of environmental pollutants. Herein, two marine’s bacterial isolates were tested for their ability to decompose crude oil. The optimum conditions for effective bacterial degradation e.g., pH, temperature, and inoculum size were investigated. PVA-alginate-clay composite hydrogel beads with different types of incorporated mineral clays were prepared and tested as bacterial carrier for potential bioremediation. Synthesized composite hydrogels were physico-chemically characterized by FTIR, SEM, and thermal analyses. Results showed that, embedded degrading bacteria in PVA-alginate beads recorded degradation rates as 74 and 66.6% for both tested bacterial isolates (S and R) compared to 61.2 and 53% degradation rates by free cells, respectively. Where, attapulgite clay-containing beads recorded maximum degradation% as 78.8 and 75% for both bacterial isolates, when added to immobilization matrices and these percentages could be enhanced under optimal conditions. The 16S rRNA gene of the two marine oils degrading bacterial isolates were amplified and sequenced, where both isolates were identified as Pseudomonas stutzeri and Rhodococcus qingshengii with submitted accession numbers of ON908963 and ON908962, respectively. These results are referring to the ability of using both tested isolates for crude oil bioremediation process and embedded them into PVA-alginate-clay beads as hydrogel carrier under the optimum conditions.

“Statistical Optimization of Bio Diesel Production from Waste Cooking Oil Using Pva -Alginate Immobilized Lipase Enzyme as Bio Catalyst”

The present research work emphasis on immobilization of lipase on PVA-alginate beads, which are used for biodiesel production via transesterification. The optimization of temperature, pH, and reusability of was performed on PVA-Alginate beads. The highest enzyme activity was found at a temperature of 40°C and pH 4.00. After six consecutive cycles of using the immobilized enzyme, the residual activity was 60% of the initial activity. The immobilized beads were stored at 4°C without buffer after 6 weeks, the immobilized enzyme retained 76.62% of initial activity.. The second-order mathematical model was developed using RSM. Transesterification process parameters were optimized by using ‘Full Factorial Design’ (FFD) with free lipase and immobilized lipase. The different factors considered for optimization were methanol/oil (M/O) ratio, reaction time, the weight of the catalyst with constant temperature and agitation speed. FFD was performed for free lipase, obtained the highest yield with optimum conditions; M/O ratio 9:1, reaction time 90 minutes, and weight of the catalyst was 0.3gm. Similarly, FFD was performed with immobilized lipase with the highest yield at 6:1 M/O ratio, 3 hours reaction time, the weight of the catalyst 3gm. FTIR was performed for the PVA-Alginate beads and lipase immobilized PVA-Alginate beads From FTIR spectra, the peaks shift from 1746 cm -1 to 1742 cm -1 signified the formation of biodiesel.

Enhancement of phenol degradation by free and immobilized mixed culture of Providencia stuartii PL4 and Pseudomonas aeruginosa PDM isolated from activated sludge

Biodegradation of phenol has been investigated using a bacterial consortium consisting of two bacterial isolates; one of them used for the first time in phenol biodegradation. This consortium was isolated from activated sludge and identified as Providencia stuartii PL4 and Pseudomonas aeruginosa PDM (accession numbers KY848366 and MF445102, respectively). The degradation of phenol by this consortium was optimal at pH 7 with using 1500 mg l−1 ammonium chloride as a nitrogen source. Interestingly, after optimizing the biodegradation conditions, this consortium was able to degrade phenol completely up to 1500 mg l−1 within 58 h. The immobilization of this consortium on various supporting materials indicated that polyvinyl alcohol (PVA)-alginate beads and polyurethane foam (PUF) were more suitable for biodegradation process. The freely suspended cells could degrade only 6% (150 mg l−1) of 2500 mg l−1 phenol, whereas, the immobilized PVA-alginate beads and the immobilized PUF degraded this concentration completely within 120 h of incubation with degradation rates (q) 0.4839 and 0.5368 (1/h) respectively. Thus, the immobilized consortium of P. stuartii PL4 and P. aeruginosa PDM can be considered very promising in the treatment of effluents containing phenol.

Mineral pollutants removal through immobilized microalgae-bacterial flocs in a multitrophic microreactor

ABSTRACTMicroalgae-bacterial flocs (MaB-flocs) immobilization technique using polyvinyl alcohol (PVA) crosslinked with sodium alginate represent a novel approach for sustainable pollutants removal. The present work was performed to evaluate the performance of a multitrophic batch reactor at microscale for treating two synthetic wastewater solutions prepared with two different initial Chemical Oxygen Demand (COD): 200 mg.L−1 and 450 mg.L−1, respectively. Three MaB-flocs concentrations were entrapped into PVA-alginate beads: C1 (2%, v/v), C2 (5%, v/v) and C3 (10%, v/v), without O2 supply, during three periods 2, 4 and 6 days of batch incubation. PVA-alginate beads containing the highest concentration C3 of MaB-flocs improved the performance of the microreactor to remove significantly NH4+ and PO43− of about 61% and 82%, respectively, from wastewater more than two other concentrations used. This result confirms that C3 of MaB-flocs displays not only a good potential for nutrients removals but also the highest MaB-flocs morphological progression after 6 days of treatment with the highest COD of 450 mg.L-1. The feasibility of the PVA-alginate for cells immobilization, investigated through microscopy analysis, reveals that the evolution of multicellularity in MaB-flocs, for all experiments.

Adsorption Efficiency of Polyvinyl Alcohol -Alginate Beads on Cr (VI): Effect of pH and Temperature

Chromium pollution has been an increasing worldwide concern because of its high toxicity and carcinogenic properties, in which requires efficient purification technique. In the present study, adsorbent beads containing polyvinyl alcohol (PVA) and sodium alginate were prepared by crosslinked with boric acid and calcium chloride for hexavalent chromium [Cr (VI)] removal. The adsorption experiments were carried out using batch adsorption studies at various solution pH and temperatures. The results demonstrated that the optimised solution pH and temperature were observed at 1 and 70 ⁰C, respectively. The adsorption efficiency was extremely fast and Cr (VI) was completed to be adsorbed within 45 minutes. Consequently, these results implied that the PVA-alginate beads could be considered as a potential adsorbent for Cr (VI) removal in wastewater treatment industry.

Polyvinyl Alcohol-Alginate Adsorbent Beads for Chromium (VI) Removal

Chromium pollution has been an increasing concern worldwide because of its high toxicity and carcinogenic properties, and it requires an efficient purification technique. In this study, adsorbent beads containing polyvinyl alcohol (PVA) and sodium alginate were prepared by crosslinking with boric acid and calcium chloride for adsorbent of the hexavalent chromium [Cr (VI)]. Batch adsorption studies were conducted to evaluate Cr (VI) adsorption rates of PVA-alginate beads from aqueous solution under ultraviolet (UV) light illumination. The surface morphology and elemental composition of beads were examined using field emission scanning electron microscopy (FESEM) and energy dispersive spectrometer (EDS), respectively. This study revealed that the Cr (VI) adsorption rates increased remarkably with dosages of PVA and sodium alginate. This occurred mainly due to the increasing number of the active sites for adsorption. The results revealed that adsorbent beads with 12 g of PVA and 2.5 g sodium alginate beads exhibited superior Cr (VI) adsorption efficiency at which it is completely removed after 1.5 hours. The findings of this study indicate that PVA-sodium alginate beads are a viable option for Cr (VI) removal from industrial wastewater.

Bioethanol production from galactose by immobilized wild-type Saccharomyces cerevisiae

Abstract Bioethanol has been emerging from different types of renewable feedstocks as an alternative to reduce problems caused by the use of fossil fuels. Galactose is the major sugar obtained from the hydrolysis of seaweeds and can be fermented to ethanol by yeast. Wild-type Saccharomyces cerevisiae has been reported with good performance of galactose fermentation. The first part of the study focused on the isolation and characterization of wild-type S. cerevisiae with the ability to ferment galactose to ethanol. A wild-type S. cerevisiae strain with the ability to ferment galactose to ethanol was isolated from grape with ethanol tolerance of 15%. Immobilization of yeast cells has been performed to increase the ethanol production. The second part of the study involved the immobilization of the isolated wild-type S. cerevisiae in PVA-alginate beads. Batch fermentation of galactose by immobilized wild-type S. cerevisiae obtained ethanol concentration and yield efficiency of 9.57 g/L and 93.82%. The immobilized wild-type S. cerevisiae were used for four cycles of galactose fermentation and obtained ethanol concentration of 7.66 g/L with yeast relative activity of 79.07%. In short, bioethanol produced by galactose fermenting wild-type S. cerevisiae can be a future sustainable fuel.

Influence of the reaction parameters on biodiesel production catalyzed by a lipase from Thermomyces lanuginosus immobilized in PVA-alginate beads

ABSTRACTWaste frying oil (WFO) was used in biodiesel production using a lipase from Thermomyces lanuginosus immobilized in poly(vinyl alcohol) (PVA)-alginate beads as catalyst. The effect of parameters such as temperature, oil/methanol ratio, water content, and agitation speed on the conversion of methyl esters was studied. Fatty acid methyl esters composition was determined by gas chromatography mass spectrometry. Biodiesel yield of 92 wt% ± 0.6 was obtained at an oil/methanol molar ratio of 1:6, 400 rpm, 45 °C and methanol purity of 99.99% after 90 h of reaction.

Novel characteristics of horseradish peroxidase immobilized onto the polyvinyl alcohol-alginate beads and its methyl orange degradation potential

Herein, we report the immobilization of in-house isolated horseradish peroxidase (HRP) from Armoracia rusticana with novel characteristics. The HRP was immobilized onto the self-fabricated polyvinyl alcohol-alginate (PVA-alginate) beads using sodium nitrate as a cross-linker. The PVA-alginate beads (2.0mm size) developed using 10% PVA and 1.5% sodium alginate showed maximal immobilization yield. The surface morphologies of the PVA-alginate (control) and immobilized-HRP were characterized by scanning electron microscopy (SEM). The immobilized-HRP retained 64.14% of its initial activity after 10 consecutive substrate-oxidation cycles as compared to the free counterpart. Simultaneously, the thermal stability of the immobilized-HRP was significantly enhanced as compared to the free HRP. The enzyme leakage (EL) assay was performed by storing the immobilized-HRP in phosphate buffer solution for 30days. Evidently, the leakage of immobilized-HRP was recorded to be 6.98% and 14.82% after 15 and 30days of incubation, respectively. Finally, the immobilized-HRP was used for methyl orange (MO) dye degradation in a batch mode. A noticeable decline in spectral shift accompanied by no appearance of a new peak demonstrated the complete degradation of MO. The degraded fragments of MO were scrutinized by ultra-performance liquid chromatography coupled with mass spectrometry (UPLC–MS). A plausible degradation pathway for MO was proposed based on the identified intermediates. In conclusion, the study portrays the PVA-alginate-immobilized-HRP as a cost-effective and industrially desirable green catalyst, for biotechnological at large and industrial in particular, especially for the treatment of textile dyes or dye-containing industrial waste effluents.

Improving Whole-Cell Biocatalysis by Addition of Deep Eutectic Solvents and Natural Deep Eutectic Solvents

Being considered greener alternatives to ionic liquids (IL), deep eutectic solvents (DES) and natural deep eutectic solvents (NADES) have currently attracted broad interests from academics and industry. In this study, the transformation of isoeugenol to vanillin catalyzed by Lysinibacillus fusiformis CGMCC1347 cells was taken as the model reaction to examine the impacts of 24 DESs and 21 NADESs as cosolvents on whole-cell biocatalysis. Both types of cosolvents showed the ability of improving the production yields up to 142% and 132% of the ones obtained in (NA)DES-free aqueous systems, respectively. The data obtained by confocal laser scanning microscopy and flow cytometry tests and measurements of OD260 and OD280 agreed well with the bioconversion data, suggesting that addition of these cosolvents may be beneficial to whole-cell biocatalysis in enhancing the cellular membrane permeability. Interaction of DES with bacterial cell wall was discussed. The cells immobilized in PVA-alginate beads granted an augmented production yield in the presence of DES and NADES, up to 181% of the one obtained in a pure water system, and their catalytic activity was well maintained after being used for at least 13 cycles.

Biodegradation and kinetic study of benzene in bioreactor packed with PUF and alginate beads and immobilized with Bacillus sp. M3

Benzene removal in free and immobilized cells on polyurethane foam (PUF) and polyvinyl alcohol (PVA)-alginate beads was studied using an indigenous soil bacterium Bacillus sp. M3 isolated from petroleum-contaminated soil. The important process parameters (pH, temperature and inoculums size) were optimized and found to be 7, 37°C and 6.0×108CFU/mL, respectively. Benzene removals were observed to be 70, 84 and 90% within 9days in a free cell, immobilized PVA-alginate beads and PUF, respectively under optimum operating conditions. FT-IR and GC–MS analysis confirm the presence of phenol, 1,2-benzenediol, hydroquinone and benzoate as metabolites. The important kinetic parameter ratios (µmax/Ks; L/mg·day) calculated using Monod model was found to be 0.00123 for free cell, 0.00159 for immobilized alginate beads and 0.002016 for immobilized PUF. Similarly inhibition constants (Ki; mg/L) calculated using Andrew-Haldane model was found to be 435.84 for free cell, 664.25 for immobilized alginate beads and 724.93 for immobilized PUF.

Photocatalytic reduction of Cs(I) ions removed by combined maghemite-titania PVA-alginate beads from aqueous solution

The presence of Cs(I) ions in nuclear wastewater becomes an important issue for the reason of its high toxicity. The development of adsorbent embedded metal-based catalysts that has sufficient adsorption capacity is expected for the removal of Cs(I) ions from contaminated water. This study tested the use of maghemite, titania and combined maghemite-titania polyvinyl alcohol (PVA)-alginate beads as an adsorbent to remove Cs(I) ions from aqueous solution with the variables of pH and initial concentration using batch experiments under sunlight. The results showed that the use of combined maghemite-titania PVA-alginate beads can have an efficiency of 93.1% better than the use of either maghemite PVA-alginate beads with an efficiency of 91.8% or titania PVA-alginate beads with an efficiency of 90.1%. The experimental data for adsorption of Cs(I) ions from aqueous solution with the initial concentrations of 50, 100 and 200 mg L−1 on the surface of combined maghemite-titania PVA-alginate beads were well fit by the pseudo-second-order and Langmuir models. The optimal adsorption of Cs(I) ions from aqueous solution by combined maghemite-titania PVA-alginate beads under sunlight occurs at pH 8 with an initial Cs(I) ion concentration of 50 mg L−1. The combined maghemite-titania PVA-alginate beads can be recycled at least five times with a slight loss of their original properties.

Sandal reactive dyes decolorization and cytotoxicity reduction using manganese peroxidase immobilized onto polyvinyl alcohol-alginate beads.

BackgroundFungal manganese peroxidases (MnPs) have great potential as bio-remediating agents and can be used continuously in the immobilized form like many other enzymes.ResultsIn the present study, purified manganese peroxidase (MnP) enzyme isolated from Ganoderma lucidum IBL-05 was immobilized onto polyvinyl alcohol-alginate beads and investigated its potential for the decolorization and detoxification of new class of reactive dyes and textile wastewater. The optimal conditions for MnP immobilization were 10 % (w/v) PVA, 1.5 % sodium alginate, 3 % boric acid and 2 % CaCl2 solution. The optimum pH, temperature and kinetic parameters (Km and Vmax) for free and immobilized MnP were found to be significantly altered after immobilization. The immobilized MnP showed high decolorization efficiency for Sandal reactive dyes (78.14–92.29 %) and textile wastewater (61–80 %). Reusability studies showed that after six consecutive dye decolorization cycles, the PVA coupled MnP retained more than 60 % of its initial activity (64.9 % after 6th cycle form 92.29 % in 1st cycle) for Sandal-fix Foron Blue E2BLN dye. The water quality assurance parameters (BOD, COD and TOC) and cytotoxicity (haemolytic and brine shrimp lethality tests) studies before and after treatment were employed and results revealed that both the dyes aqueous solution and textile wastewater were cytotoxic that reduced significantly after treatment.ConclusionsThe decolorization and cytotoxicity outcomes indicated that immobilized MnP in PVA–alginate beads can be efficiently exploited for industrial and environmental applications, especially for remediation of textile dyes containing wastewater effluents. Graphical abstractDye decolorizing potential of immobilized MnP

Efficiency of barium removal from radioactive waste water using the combination of maghemite and titania nanoparticles in PVA and alginate beads

In this paper, both maghemite (γ-Fe2O3) and titanium oxide (TiO2) nanoparticles were synthesized and mixed in various ratios and embedded in PVA and alginate beads. Batch sorption experiments were applied for removal of barium ions from aqueous solution under sunlight using the beads. The process has been investigated as a function of pH, contact time, temperature, initial barium ion concentration and TiO2:γ-Fe2O3 ratios (1:10, 1:60 and 1). The recycling attributes of these beads were also considered. Furthermore, the results revealed that 99% of the Ba(II) was eliminated in 150min at pH 8 under sunlight. Also, the maghemite and titania PVA–alginate beads can be readily isolated from the aqueous solution after the process and reused for at least 7 times without significant losses of their initial properties. The reduction of Ba(II) with maghemite and titania PVA–alginate beads fitted the pseudo first order and second order Langmuir–Hinshelwood (L–H) kinetic model.

Photocatalytic reduction of iodine in radioactive waste water using maghemite and titania nanoparticles in PVA-alginate beads

The presence of iodine ions in nuclear waste water is a major concern due to its high level of toxicity. In this study three different types of beads were prepared; i) maghemite (γ-Fe2O3) PVA-alginate beads, ii) titania (TiO2) PVA-alginate and iii) combined γ-Fe2O3 and TiO2 nanoparticles embedded in PVA-alginate defined as maghemite and titania PVA-alginate beads respectively. These beads were used in batch sorption experiments for iodine ions removal from radioactive waste water under sunlight. The combined γ-Fe2O3 and TiO2 nanoparticles embedded in PVA-alginate was able to remove the I(1) rapidly with maximum efficiency. Results revealed that I(1) removal was enhanced under sunlight irradiation and XPS findings proved that I(1) was reduced to I(0) indicating that photocatalytic process has occurred. Maximum removal of I(1) was achieved at maximum pH of 8. The maghemite and titania PVA-alginate beads were robust; losing only 13% of its photocatalytic properties after recycling for seven times. Kinetic studies illustrated that I(1) removal followed the pseudo-second-order model with the R2 > 0.99.

Synergistic Effect of Maghemite and Titania Nanoparticles in PVA-Alginate Encapsulated Beads for Photocatalytic Reduction of Pb(II)

In this paper, maghemite (γ-Fe2O3) and titanium oxide (TiO2) nanoparticles were synthesized by hydrothermal and coprecipitation methods, respectively. These nanoparticles were combined together in various ratios (1:10, 1:20, 1:60, 1:80, and 1) and embedded in polyvinyl alcohol (PVA)-alginate beads. These beads were tested for photocatalytic behavior in eliminating toxic Pb(II) from the aqueous solution. The photocatalytic experiments were performed under sunlight irradiation and without sunlight. Several operating conditions such as initial Pb(II) concentration, pH, contact time, and TiO2: γ-Fe2O3 ratios were investigated to evaluate their effect on the process. The recycling attributes of these beads were also investigated. The results revealed that 100% of the Pb(II) was eliminated in 100 min at pH 7 under sunlight when the ratio of TiO2:γ-Fe2O3 was kept to 1. The PVA-alginate maghemite and titania beads showed better efficiency for Pb(II) removal than PVA-alginate titania beads and PVA-alginate maghemite beads. X-ray photoelectron spectroscopy (XPS) analysis also revealed that Pb(II) removal was via photocatalytic reduction due to the presence of Pb(0) in the high-resolution scan at 130–160 eV. Also, the PVA-alginate titania and maghemite beads can be readily isolated from the aqueous solution after the photocatalytic process and reused for at least 6 times without significant losses in their initial properties. The reduction of Pb(II) with PVA-alginate titania and maghemite beads fitted the Langmuir–Hinshelwood (L–H) kinetic model at a correlation coefficient (R2) of 0.9923.

Combination of maghemite and titanium oxide nanoparticles in polyvinyl alcohol-alginate encapsulated beads for cadmium ions removal

Both maghemite (γ-Fe2O3) and titanium oxide (TiO2) nanoparticles were mixed at various ratios and embedded in polyvinyl alcohol (PVA)-alginate beads. These beads were tested for photocatalytic behavior in eliminating toxic Cd(II) from the aqueous solution. The photocatalytic experiments were performed under sunlight irradiation at various pH, initial feed concentrations and γ-Fe2O3: TiO2 ratios. The recycling attribute of these beads was also investigated. The results revealed that 100% of the Cd(II) was eliminated in 150 minutes at pH 7 under sunlight. It shows that maghemite and titania PVA-alginate beads can be readily isolated from the aqueous solution after the photocatalyst process and reused for at least six times without losing their initial properties.

Photocatalyst treatment for lead(II) using titanium oxide nanoparticles embedded in PVA-alginate beads

In this paper, titanium oxide nanoparticles were produced using the hydrothermal method and embedded in PVA–alginate beads to remove Pb(II) ions from aqueous solutions. The kinetics of the photocatalyst process was elucidated by varying operating parameters such as pH (3, 7 and 10) and initial Pb(II) concentrations (25, 50, 100 and 200 mg/L). The findings revealed that 99.1% of the Pb(II) was removed within 150 min and maximum removal occurred in initial concentration of 25 mg/L at pH 7. The titania PVA-alginate beads can be readily isolated from the aqueous solutions after the photocatalytic process and reused for at least seven times without significant loss in their initial properties. In addition, the reduction of Pb(II) from wastewater using titania PVA-alginate beads fitted the Langmuir–Hinshelwood kinetic model with a correlation coefficient (R2) of 0.9931.

Copper (II) Removal by Using Manganese Ferrite in PVA-Alginate Beads

The magnetic nanoparticles of manganese-doped magnetite (Mn-Fe2O4) were synthesized by the simple co-precipitation method. The stable Mn2+ and Fe3+ salts in the ratio of 1:2 in aqueous solution, were added into the sodium hydroxide solution to form the Mn-Fe2O4 precipitate at temperature of 95°C. The synthesized nanoparticles were then characterized by Fourier Transform-Infrared Spectroscopy (FT-IR) and X-ray diffraction spectroscopy (XRD). It was then entrapped in the PVA-alginate matrix to form the nanophotoadsorbent in beads form. The synthesized nanoparticles embedded bead was characterized by Scanning Electron Microscopy (SEM). The effects of various parameters, such as contact time, pH, nanoparticles dosage were investigated. The control study was also performed to reveal the performance of photo-adsorbent towards the Cu (II) removal under the light and dark conditions. It was found that the removal efficiency of the Cu (II) achieved 97.07% (1.46ppm) which complied to the WHO drinking water standard of less than 1.5ppm after 180 min treatment.

Removal of barium from radioactive aqueous solution by PVA–alginate encapsulated titanium oxide using sunlight and other light types

TiO2 NPs were synthesized by hydrothermal method. TiO2 PVA–alginate beads were used for barium ion removal from wastewater, removing 98% of Ba2+ in 130 min at pH 8 by sunlight, and the beads could be reused 5 times. Ba2+ reduction fitted the pseudo second-order rate model.