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Paluch D, Bazan-Wozniak A, Pietrzak R. Methyl Red Adsorption on Biochar Obtained by Physical Activation of Caraway Seeds with Carbon Dioxide. Chemphyschem 2024; 25:e202300821. [PMID: 38180792 DOI: 10.1002/cphc.202300821] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2023] [Revised: 01/05/2024] [Accepted: 01/05/2024] [Indexed: 01/06/2024]
Abstract
In this study carbon adsorbents were produced from caraway (Carum carvi L.) seeds, through direct and physical activation by carbon dioxide. The resulting biochar adsorbents were analyzed using low-temperature nitrogen adsorption-desorption isotherms and Boehm titration. Furthermore, the acid-base properties of the biochar samples obtained were examined, and the pH of their aqueous extracts was determined. The obtained adsorbents had a specific surface area ranging between 10 to 70 m2 /g. Resulting carbon materials exhibited a predominance of basic groups on their surfaces. The sorption capacities of methyl red for the samples varied from 3 to 20 mg/g. Conducted adsorption studies determined, that the adsorption kinetics of the dye on biochar materials followed a pseudo-second order model and the adsorption process was best described by the Freundlich isotherm, indicating the development of a multi-layer adsorbate on their surfaces. The effectiveness of adsorption in aqueous solutions of methyl red increased with the rise in process temperature. Moreover, the adsorption process was found to be spontaneous and endothermic based on thermodynamic investigations.
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Affiliation(s)
- Dorota Paluch
- Department of Applied Chemistry, Faculty of Chemistry, Adam Mickiewicz University in Poznań, Uniwersytetu Poznańskiego 8, 61-614, Poznań, Poland
| | - Aleksandra Bazan-Wozniak
- Department of Applied Chemistry, Faculty of Chemistry, Adam Mickiewicz University in Poznań, Uniwersytetu Poznańskiego 8, 61-614, Poznań, Poland
| | - Robert Pietrzak
- Department of Applied Chemistry, Faculty of Chemistry, Adam Mickiewicz University in Poznań, Uniwersytetu Poznańskiego 8, 61-614, Poznań, Poland
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Kaya N, Carus Özkeser E, Yıldız Uzun Z. Investigating the effectiveness of rice husk-derived low-cost activated carbon in removing environmental pollutants: a study of its characterization. Int J Phytoremediation 2024; 26:427-447. [PMID: 37583119 DOI: 10.1080/15226514.2023.2246584] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/17/2023]
Abstract
The chemically activated biochar was produced through the pyrolysis of rice husk. Thermal gravimetric and elemental analysis were conducted to characterize the raw rice husk. The activated biochar product underwent evaluation through SEM, BET and, FT-IR analysis. This cost-effective activated carbon was utilized as an adsorbent for the elimination of environmental pollutants. At a temperature of 25 °C, the activated biochar product exhibited an impressive maximum CO2 adsorption capacity of 152 mg/g. This exceptional performance can be attributed to its notable surface area and porosity, measuring at 2,298 m2/g and 0.812 cm3/g, respectively. This product was also utilized to remove methyl red (MR) dye from an aqueous solution. The optimal parameters for the removal of MR were determined as follows: a pH of 6.0, a temperature of 25 °C, an initial MR concentration of 50 mg/L, and an adsorbent dosage of 0.4 g/L. At a duration of 140 min, the system attained its maximum equilibrium adsorption capacity, reaching a value of 62.06 mg/g. Furthermore, the calculated maximum MR removal efficiency stood at an impressive 99.31%. The thermodynamic studies demonstrated that the MR removal process was spontaneous, exothermic, and increased randomness. Kinetic studies suggested that the pseudo-second-order model can fit well.
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Affiliation(s)
- Nihan Kaya
- Department of Chemical Engineering, Ondokuz Mayıs University, Samsun, Turkey
| | | | - Zeynep Yıldız Uzun
- Department of Chemistry and Chemical Processing Technologies, Sinop University, Sinop, Turkey
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Paluch D, Bazan-Wozniak A, Wolski R, Nosal-Wiercińska A, Pietrzak R. Removal of Methyl Red from Aqueous Solution Using Biochar Derived from Fennel Seeds. Molecules 2023; 28:7786. [PMID: 38067516 PMCID: PMC10708363 DOI: 10.3390/molecules28237786] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2023] [Revised: 11/22/2023] [Accepted: 11/24/2023] [Indexed: 12/18/2023] Open
Abstract
In this study, fennel (Foeniculum vulgare) seeds were used as a precursor to obtain carbon adsorbents through physical activation with carbon dioxide and chemical activation by impregnating the precursor with sodium carbonate. The physical activation involved the carbonization of the precursor at a temperature of 600 °C for 60 min and activation at a temperature of 800 °C for 30 min with carbon dioxide. Chemical activation included impregnation of the precursor with sodium carbonate at a mass ratio of a precursor to activator of 1:2. The mixture was activated in a nitrogen atmosphere with a flow rate at a temperature of 700 °C for 45 min. The resulting biochar samples were washed with 5% hydrochloric acid and subsequently rinsed with boiling distilled water. The biochar adsorbents were characterized using low-temperature nitrogen adsorption-desorption isotherms, Boehm titration, and pH measurements of their aqueous extracts. The specific surface area of the obtained adsorbents ranged from 89 to 345 m2/g. Biochar adsorbents exhibit a predominance of acidic groups over basic groups on their surfaces. The sorption capacities of the obtained samples towards an aqueous solution of methyl red range from 26 to 135 mg/g. Based on adsorption studies, it was found that the adsorption of the dye on the obtained biochar materials follows a pseudo-second-order model. The Freundlich isotherm best describes the studied process, indicating the formation of a multilayer of adsorbate on the adsorbent surface. The efficacy of adsorption in aqueous solutions of methyl red was found to increase with the elevation of the process temperature. Moreover, thermodynamic studies have shown that the adsorption process is spontaneous and endothermic. Consequently, this work provides a description of the physicochemical parameters of two biochars obtained by physical and chemical activation of a little-studied precursor-fennel seeds-and studies on their potential use as adsorbents for contaminants from the aqueous phase.
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Affiliation(s)
- Dorota Paluch
- Department of Applied Chemistry, Faculty of Chemistry, Adam Mickiewicz University in Poznań, Uniwersytetu Poznańskiego 8, 61-614 Poznan, Poland; (D.P.); (A.B.-W.); (R.W.)
| | - Aleksandra Bazan-Wozniak
- Department of Applied Chemistry, Faculty of Chemistry, Adam Mickiewicz University in Poznań, Uniwersytetu Poznańskiego 8, 61-614 Poznan, Poland; (D.P.); (A.B.-W.); (R.W.)
| | - Robert Wolski
- Department of Applied Chemistry, Faculty of Chemistry, Adam Mickiewicz University in Poznań, Uniwersytetu Poznańskiego 8, 61-614 Poznan, Poland; (D.P.); (A.B.-W.); (R.W.)
| | - Agnieszka Nosal-Wiercińska
- Department of Analytical Chemistry, Institute of Chemical Sciences, Faculty of Chemistry, Maria Curie-Sklodowska University, Maria Curie-Sklodowska Sq. 3, 20-031 Lublin, Poland;
| | - Robert Pietrzak
- Department of Applied Chemistry, Faculty of Chemistry, Adam Mickiewicz University in Poznań, Uniwersytetu Poznańskiego 8, 61-614 Poznan, Poland; (D.P.); (A.B.-W.); (R.W.)
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Zhang S, Yao Y, Li J, Wang L, Wang X, Tian S. Multi-factorial investigation of the effect of biochar of the secondary medicinal residue of snow lotus on the adsorption of two azo dyes, methyl red and methyl orange. Microsc Res Tech 2023; 86:1416-1442. [PMID: 37177906 DOI: 10.1002/jemt.24343] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2023] [Revised: 04/25/2023] [Accepted: 05/02/2023] [Indexed: 05/15/2023]
Abstract
Azo dye residues pollute water, which are difficult to decompose, and posing a major threat to the ecological environment. The residues of Chinese medicine still have many possibilities for use after its medicinal value has been brought into play. In this study, secondary residue biochar activation (Na2 CO3 -modified, SBA) and secondary residue biochar (unmodified, SBC) were prepared from the secondary residue of snow lotus at 200-600°C. Surface features were obtained by Brunauer-Emmett-Teller N2 method and combined with scanning electron microscopy, and their structures were analyzed by x-ray diffraction spectroscopy, Fourier infrared and near-infrared spectroscopy. The effects of five factors, including initial concentration, contact time and adsorption temperature and so forth, on the adsorption of methyl red (MR) and methyl orange (MO) solutions were investigated. Results showed that the biochar yield, specific surface area, and pore size increased after modification. modification promoted the formation of the internal structure aromatization and oxygen-containing functional groups. Adsorption experiments showed that the surroundings pH = 8, the dyes adsorption concentration of 8 mg/L, adsorption temperature of 20-40°C and time of about 1 h were more stable. Under the condition, the removal of MO by SBA could reach approximately 60%-80% (480-640 mg/g), while the removal of MR could reach more than 90% (>720 mg/g).The charcoal prepared and modified under high temperature conditions was more effective for MO adsorption, while MR relied on low temperature effectively. This study provides a new choice of adsorbent for MR and MO and finds a new direction for the utilization of snow lotus residues.
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Affiliation(s)
- Sha Zhang
- College of Traditional Chinese Medicine, Xinjiang Medical University, Urumqi, Xinjiang, China
| | - Yanna Yao
- R&D department, Xinjiang Tianshan Lian Pharmaceutical (Co., Ltd.), Changji, Xinjiang, China
| | - Junlong Li
- College of Traditional Chinese Medicine, Xinjiang Medical University, Urumqi, Xinjiang, China
| | - Linyang Wang
- College of Traditional Chinese Medicine, Xinjiang Medical University, Urumqi, Xinjiang, China
| | - Xinyu Wang
- R&D department, Xinjiang Tianshan Lian Pharmaceutical (Co., Ltd.), Changji, Xinjiang, China
| | - Shuge Tian
- College of Traditional Chinese Medicine, Xinjiang Medical University, Urumqi, Xinjiang, China
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Paluch D, Bazan-Wozniak A, Nosal-Wiercińska A, Pietrzak R. Removal of Methylene Blue and Methyl Red from Aqueous Solutions Using Activated Carbons Obtained by Chemical Activation of Caraway Seed. Molecules 2023; 28:6306. [PMID: 37687135 PMCID: PMC10488674 DOI: 10.3390/molecules28176306] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2023] [Revised: 08/25/2023] [Accepted: 08/27/2023] [Indexed: 09/10/2023] Open
Abstract
In this study, activated carbons were produced through the chemical activation of caraway seeds using three different activators: Na2CO3, K2CO3, and H3PO4. A 1:2 weight ratio of precursor to activator was maintained in every instance. Comprehensive analyses were conducted on the resultant activated carbons, including elemental analysis, textural parameters determination, Boehm titration for surface oxygen functional groups, pH assessment of aqueous extracts, and quantification of ash content. The produced materials were subjected to adsorption tests for methylene blue and methyl red sodium salt from the liquid phase and the effects of adsorbent dosage, pH of the aqueous dye solution, process temperature, and adsorbent-adsorbate contact time on sorption capacity obtained. To characterize the adsorption model of the examined pollutants, both the Langmuir and Freundlich equations were employed. In addition, the sorption capacity of the obtained carbon materials against an iodine aqueous solution was assessed. The specific surface area of the obtained adsorbents ranged from 269 to 926 m2/g. By employing potassium carbonate to chemically activate the starting substance, the resulting activated carbons show the highest level of specific surface area development and the greatest sorption capacity against the tested impurities-296 mg/g for methylene blue and 208 mg/g for methyl red sodium salt. The adsorption rate for both dyes was determined to align with a pseudo-second-order kinetic model. The experimental adsorption data for methylene blue were well-described by the Langmuir model, whereas the Freundlich model was found to be congruent with the data pertaining to methyl red sodium salt.
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Affiliation(s)
- Dorota Paluch
- Department of Applied Chemistry, Faculty of Chemistry, Adam Mickiewicz University in Poznan, Uniwersytetu Poznanskiego 8, 61-614 Poznan, Poland; (D.P.); (A.B.-W.); (R.P.)
| | - Aleksandra Bazan-Wozniak
- Department of Applied Chemistry, Faculty of Chemistry, Adam Mickiewicz University in Poznan, Uniwersytetu Poznanskiego 8, 61-614 Poznan, Poland; (D.P.); (A.B.-W.); (R.P.)
| | - Agnieszka Nosal-Wiercińska
- Department of Analytical Chemistry, Institute of Chemical Sciences, Faculty of Chemistry, Maria Curie-Sklodowska University in Lublin, Maria Curie-Sklodowska Sq. 3, 20-031 Lublin, Poland
| | - Robert Pietrzak
- Department of Applied Chemistry, Faculty of Chemistry, Adam Mickiewicz University in Poznan, Uniwersytetu Poznanskiego 8, 61-614 Poznan, Poland; (D.P.); (A.B.-W.); (R.P.)
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Yang F, He X, Xin T, Yang H, Bai L, Gao L, Wang Y. A Series of Polymer-Supported Polyoxometalates as Heterogeneous Photocatalysts for Degradation of Organic Dye. Molecules 2023; 28:molecules28093968. [PMID: 37175373 PMCID: PMC10179983 DOI: 10.3390/molecules28093968] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2023] [Revised: 05/01/2023] [Accepted: 05/04/2023] [Indexed: 05/15/2023] Open
Abstract
Photocatalytic degradation technology has developed rapidly in the treatment of organic pollutants due to its high efficiency, mild reaction conditions and easy control. In this paper, a series of heterogeneous photocatalysts, BWZ-en-R (BWZ = [BW11Z(H2O)O39]7-, Z = Zn, Cd, Mn, en = ethylenediamine, R = Merrifield resin), were prepared by using ethanediamine as a linker to immobilize Keggin-type transition elements substituting tungstoborates on Merrifield resin and characterized by Fourier transform infrared spectroscopy, X-ray powder diffraction, scanning electron microscopy and energy-dispersive X-ray spectroscopy. The photocatalytic properties of BWZ-en-R (Z = Zn, Cd, Mn) for the degradation of methyl red (MR) were investigated. The results show that the BWZ-en-R (Z = Zn, Cd, Mn) photocatalysts exhibited high photodegradation ability for MR under the irradiation of ultraviolet light, and were easily separated from the reaction media. The maximum degradation rate (%) of MR (40 mL, 25 μM, pH = 2) reached 96.4% for the BWMn-en-R photocatalyst (40 mg) after being irradiated for 30 min, making this a promising photocatalyst candidate for dye degradation. Moreover, the influences of some factors, such as the Z-substituted elements in the BWZ, the BWZ-en-R dosage and the MR initial concentration, on the photocatalytic degradation rate of MR were also examined.
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Affiliation(s)
- Fan Yang
- Department of Chemistry, Beijing Technology and Business University, Beijing 100048, China
| | - Xiaojiao He
- Department of Chemistry, Beijing Technology and Business University, Beijing 100048, China
| | - Tingting Xin
- Department of Chemistry, Beijing Technology and Business University, Beijing 100048, China
| | - Huizhen Yang
- Department of Chemistry, Beijing Technology and Business University, Beijing 100048, China
| | - Lijie Bai
- Department of Chemistry, Beijing Technology and Business University, Beijing 100048, China
| | - Lihua Gao
- Department of Chemistry, Beijing Technology and Business University, Beijing 100048, China
| | - Yibo Wang
- Department of Chemistry, Beijing Technology and Business University, Beijing 100048, China
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Ikram M, Naeem M, Zahoor M, Rahim A, Hanafiah MM, Oyekanmi AA, Shah AB, Mahnashi MH, Al Ali A, Jalal NA, Bantun F, Sadiq A. Biodegradation of Azo Dye Methyl Red by Pseudomonas aeruginosa: Optimization of Process Conditions. Int J Environ Res Public Health 2022; 19:ijerph19169962. [PMID: 36011598 PMCID: PMC9408507 DOI: 10.3390/ijerph19169962] [Citation(s) in RCA: 15] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/09/2022] [Revised: 08/01/2022] [Accepted: 08/08/2022] [Indexed: 06/01/2023]
Abstract
Water pollution due to textile dyes is a serious threat to every life form. Bacteria can degrade and detoxify toxic dyes present in textile effluents and wastewater. The present study aimed to evaluate the degradation potential of eleven bacterial strains for azo dye methyl red. The optimum degradation efficiency was obtained using P. aeruginosa. It was found from initial screening results that P. aeruginosa is the most potent strain with 81.49% degradation activity and hence it was subsequently used in other degradation experiments. To optimize the degradation conditions, a number of experiments were conducted where only one variable was varied at a time and where maximum degradation was observed at 20 ppm dye concentration, 1666.67 mg/L glucose concentration, 666.66 mg/L sodium chloride concentration, pH 9, temperature 40 °C, 1000 mg/L urea concentration, 3 days incubation period, and 66.66 mg/L hydroquinone (redox mediator). The interactive effect of pH, incubation time, temperature, and dye concentration in a second-order quadratic optimization of process conditions was found to further enhance the biodegradation efficiency of P. aeruginosa by 88.37%. The metabolites of the aliquot mixture of the optimized conditions were analyzed using Fourier transform infrared (FTIR), GC-MS, proton, and carbon 13 Nuclear Magnetic Resonance (NMR) spectroscopic techniques. FTIR results confirmed the reduction of the azo bond of methyl red. The Gas Chromatography-Mass Spectrometry (GC-MS) results revealed that the degraded dye contains benzoic acid and o-xylene as the predominant constituents. Even benzoic acid was isolated from the silica gel column and identified by 1H and 13C NMR spectroscopy. These results indicated that P. aeruginosa can be utilized as an efficient strain for the detoxification and remediation of industrial wastewater containing methyl red and other azo dyes.
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Affiliation(s)
- Muhammad Ikram
- Department of Chemistry, Abdul Wali Khan University Mardan, Mardan 23200, Pakistan
| | - Mohammad Naeem
- Department of Chemistry, Abdul Wali Khan University Mardan, Mardan 23200, Pakistan
| | - Muhammad Zahoor
- Department of Biochemistry, University of Malakand at Chakdara, Chakdara 18800, Dir Lower Khyber Pakhtunkhwa, Pakistan
| | - Abdur Rahim
- Department of Zoology, University of Malakand at Chakdara, Chakdara 18800, Dir Lower Khyber Pakhtunkhwa, Pakistan
| | - Marlia Mohd Hanafiah
- Department of Earth Sciences and Environment, Faculty of Science and Technology, Universiti Kebangsaan Malaysia, Bangi 43600, Selangor Darul Ehsan, Malaysia
- Centre for Tropical Climate Change System, Institute of Climate Change, Universiti Kebangsaan Malaysia, Bangi 43600, Selangor, Malaysia
| | - Adeleke Abdulrahman Oyekanmi
- Department of Earth Sciences and Environment, Faculty of Science and Technology, Universiti Kebangsaan Malaysia, Bangi 43600, Selangor Darul Ehsan, Malaysia
| | - Abdul Bari Shah
- Division of Applied Life Science (BK21 Plus), Institute of Agriculture and Life Sciences, Gyeongsang National University, Jinju 52828, Korea
| | - Mater H. Mahnashi
- Department of Pharmaceutical Chemistry, College of Pharmacy, Najran University, Najran 66462, Saudi Arabia
| | - Amer Al Ali
- Department of Clinical Laboratory Sciences, Faculty of Applied Medical Sciences, University of Bisha, 255, Al Nakhil, Bisha 67714, Saudi Arabia
| | - Naif A. Jalal
- Department of Microbiology, Faculty of Medicine, Umm Al-Qura University, Makkah 24382, Saudi Arabia
| | - Farkad Bantun
- Department of Microbiology, Faculty of Medicine, Umm Al-Qura University, Makkah 24382, Saudi Arabia
| | - Abdul Sadiq
- Department of Pharmacy, Faculty of Biological Sciences, University of Malakand, Chakdara 18800, Dir Lower Khyber Pakhtunkhwa, Pakistan
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Afsharpour M, Elyasi M, Javadian H. A Novel N-Doped Nanoporous Bio-Graphene Synthesized from Pistacia lentiscus Gum and Its Nanocomposite with WO 3 Nanoparticles: Visible-Light-Driven Photocatalytic Activity. Molecules 2021; 26:6569. [PMID: 34770977 DOI: 10.3390/molecules26216569] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2021] [Revised: 10/23/2021] [Accepted: 10/27/2021] [Indexed: 11/16/2022] Open
Abstract
This paper reports the synthesis of a new nitrogen-doped porous bio-graphene (NPBG) with a specific biomorphic structure, using Pistacia lentiscus as a natural carbon source containing nitrogen that also acts as a bio-template. The obtained NPBG demonstrated the unique feature of doped nitrogen with a 3D nanoporous structure. Next, a WO3/N-doped porous bio-graphene nanocomposite (WO3/NPBG-NC) was synthesized, and the products were characterized using XPS, SEM, TEM, FT-IR, EDX, XRD, and Raman analyses. The presence of nitrogen doped in the structure of the bio-graphene (BG) was confirmed to be pyridinic-N and pyrrolic-N with N1 peaks at 398.3 eV and 400.5 eV, respectively. The photocatalytic degradation of the anionic azo dyes and drugs was investigated, and the results indicated that the obtained NPBG with a high surface area (151.98 m2/g), unique electronic properties, and modified surface improved the adsorption and photocatalytic properties in combination with WO3 nanoparticles (WO3-NPs) as an effective visible-light-driven photocatalyst. The synthesized WO3/NPBG-NC with a surface area of 226.92 m2/g displayed lower bandgap and higher electron transfer compared with blank WO3-NPs, leading to an increase in the photocatalytic performance through the enhancement of the separation of charge and a reduction in the recombination rate. At the optimum conditions of 0.015 g of the nanocomposite, a contact time of 15 min, and 100 mg/L of dyes, the removal percentages were 100%, 99.8%, and 98% for methyl red (MR), Congo red (CR), and methyl orange (MO), respectively. In the case of the drugs, 99% and 87% of tetracycline and acetaminophen, respectively, at a concentration of 10 mg/L, were removed after 20 min.
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Ran R, Wang L, Su Y, He S, He B, Li C, Wang C, Liu Y, Chen S. Preparation of pH-indicator films based on soy protein isolate/bromothymol blue and methyl red for monitoring fresh-cut apple freshness. J Food Sci 2021; 86:4594-4610. [PMID: 34392537 DOI: 10.1111/1750-3841.15884] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2021] [Revised: 06/26/2021] [Accepted: 07/22/2021] [Indexed: 01/17/2023]
Abstract
Intelligent pH-indicator films based on soy protein isolate (SPI) were prepared using pH-sensitive dyes (bromothymol blue and methyl red). The addition of mixed indicators imparts pH-indicator films with an appreciable microstructure, acceptable water resistance, and favorable optical properties. The incorporation of the mixed indicators did not lead to significant improvement in the mechanical properties of films due to weak ionic cross-linking by hydrogen bonding between the SPI macromolecules and low-molecular-weight indicators. Fourier-transform infrared spectroscopy indicated hydrogen bond-mediated intermolecular interactions, and scanning electron microscopy showed that BB/MR were well dispersed in the SPI film. The indicator addition hindered the sorption and passage of water molecules. The water vapor permeability, moisture sorption, moisture content, and total soluble matter were 4.32 to 6.12 ×10-12 g·cm/cm2 ·s·Pa, 36.70% to 73.33%, 25.28% to 44.11%, and 8.21% to 25.56%, respectively. Also, the addition of indicators reduced UV light transmittance with minimal effect on the transparency of the film. The presence of indicators enhanced the pH sensitivity, seen as a visible color reaction at different pHs (total color difference, ΔE > 5). When the pH-indicator film containing 8 ml/100 ml final film emulsions was used to monitor the fresh-cut apple freshness, a green color for fresh status was observed, which turned blue after 60 h. Collectively, our findings suggested that indicator-containing SPI films have the potential for monitoring the freshness of fruits. PRACTICAL APPLICATION: pH-indicator films can help consumers to identify the freshness of packaged food by a change in the color of the packaging material, which is easily visible to the unaided eye without the need for opening the packaging. This protects consumers' interests.
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Affiliation(s)
- Ruimin Ran
- College of Food Science, Sichuan Agricultural University, Ya'an, Sichuan Province, China
| | - Luyao Wang
- College of Food Science, Sichuan Agricultural University, Ya'an, Sichuan Province, China
| | - Yuhang Su
- School of Ocean Science and Biochemistry Engineering, Fujian Normal University Fuqing Branch, Fujian Province, Fuzhou, China
| | - Shujian He
- College of Food Science, Sichuan Agricultural University, Ya'an, Sichuan Province, China
| | - Binbin He
- College of Food Science, Sichuan Agricultural University, Ya'an, Sichuan Province, China
| | - Cheng Li
- College of Food Science, Sichuan Agricultural University, Ya'an, Sichuan Province, China
| | - Caixia Wang
- College of Food Science, Sichuan Agricultural University, Ya'an, Sichuan Province, China
| | - Yuntao Liu
- College of Food Science, Sichuan Agricultural University, Ya'an, Sichuan Province, China
| | - Saiyan Chen
- College of Food Science, Sichuan Agricultural University, Ya'an, Sichuan Province, China
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Abstract
In the present study, locally isolated Rhodococcus strains were attempted as biological tools for methyl red removal, a mutagenic azo dye posing threat to the environment if left untreated. Rhodococcus strain UCC 0016 demonstrated superior methyl red-decolourizing activity of 100% after 24 h at static condition in comparison to Rhodococcus strain UCC 0008 which recorded 65% decolourization after 72 h. Optimization of physicochemical parameters at 30°C, pH 7 and supplementing glucose as the carbon source resulted in improved methyl red-decolourizing activity at static condition and reduced the time taken to achieve complete decolourization by 80%. Higher concentration of methyl red (5 g/L) was able to be decolourized completely within 10 h by adopting the technology of immobilization. The encapsulated cells of Rhodococcus strain UCC 0016 demonstrated higher substrate affinity (Km = 0.6995 g/L) and an accelerated rate of disappearance of methyl red (Vmax = 0.3203 g/L/h) compared to the free cells. Furthermore, the gellan gum beads could be reused up to nine batches without substantial loss in the catalytic activity indicating the economic importance of this protocol. Analysis of methyl red degradation products revealed no germination inhibition on Triticum aestivum and Vigna radiata demonstrating complete toxicity removal of the parent dye after biological treatment. The occurrence of new and altered peaks (UV-Vis and FTIR) further supported the notion that the removal of methyl red by Rhodococcus strain UCC 0016 was indeed through biodegradation. Therefore, this strain has a huge potential as a candidate for efficient bioremediation of wastewater containing methyl red.
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Affiliation(s)
| | - Abdul Latif Ibrahim
- Institute of Bio-IT Selangor, Universiti Selangor, Shah Alam, Selangor Darul Ehsan, Malaysia
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