Displaying publications 101 - 120 of 452 in total

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  1. Fulltext Subcritical Water Technology for Enhanced Extraction of Biochemical Compounds from Chlorella vulgaris
    Awaluddin SA, Thiruvenkadam S, Izhar S, Hiroyuki Y, Danquah MK, Harun R
    Biomed Res Int, 2016;2016:5816974.
    PMID: 27366748 DOI: 10.1155/2016/5816974
    Subcritical water extraction (SWE) technology has been used for the extraction of active compounds from different biomass materials with low process cost, mild operating conditions, short process times, and environmental sustainability. With the limited application of the technology to microalgal biomass, this work investigates parametrically the potential of subcritical water for high-yield extraction of biochemicals such as carbohydrates and proteins from microalgal biomass. The SWE process was optimized using central composite design (CCD) under varying process conditions of temperature (180-374°C), extraction time (1-20 min), biomass particulate size (38-250 μm), and microalgal biomass loading (5-40 wt.%). Chlorella vulgaris used in this study shows high volatile matter (83.5 wt.%) and carbon content (47.11 wt.%), giving advantage as a feedstock for biofuel production. The results showed maximum total carbohydrate content and protein yields of 14.2 g/100 g and 31.2 g/100 g, respectively, achieved under the process conditions of 277°C, 5% of microalgal biomass loading, and 5 min extraction time. Statistical analysis revealed that, of all the parameters investigated, temperature is the most critical during SWE of microalgal biomass for protein and carbohydrate production.
    Matched MeSH terms: Water/chemistry*
  2. Generalized classification modeling of activated sludge process based on microscopic image analysis
    Khan MB, Nisar H, Ng CA, Lo PK, Yap VV
    Environ Technol, 2018 Jan;39(1):24-34.
    PMID: 28278778 DOI: 10.1080/09593330.2017.1293166
    The state of activated sludge wastewater treatment process (AS WWTP) is conventionally identified by physico-chemical measurements which are costly, time-consuming and have associated environmental hazards. Image processing and analysis-based linear regression modeling has been used to monitor the AS WWTP. But it is plant- and state-specific in the sense that it cannot be generalized to multiple plants and states. Generalized classification modeling for state identification is the main objective of this work. By generalized classification, we mean that the identification model does not require any prior information about the state of the plant, and the resultant identification is valid for any plant in any state. In this paper, the generalized classification model for the AS process is proposed based on features extracted using morphological parameters of flocs. The images of the AS samples, collected from aeration tanks of nine plants, are acquired through bright-field microscopy. Feature-selection is performed in context of classification using sequential feature selection and least absolute shrinkage and selection operator. A support vector machine (SVM)-based state identification strategy was proposed with a new agreement solver module for imbalanced data of the states of AS plants. The classification results were compared with state-of-the-art multiclass SVMs (one-vs.-one and one-vs.-all), and ensemble classifiers using the performance metrics: accuracy, recall, specificity, precision, F measure and kappa coefficient (κ). The proposed strategy exhibits better results by identification of different states of different plants with accuracy 0.9423, and κ 0.6681 for the minority class data of bulking.
    Matched MeSH terms: Waste Water/chemistry
  3. Recovery of biotechnological products using aqueous two phase systems
    Phong WN, Show PL, Chow YH, Ling TC
    J Biosci Bioeng, 2018 Sep;126(3):273-281.
    PMID: 29673987 DOI: 10.1016/j.jbiosc.2018.03.005
    Aqueous two-phase system (ATPS) has been suggested as a promising separation tool in the biotechnological industry. This liquid-liquid extraction technique represents an interesting advance in downstream processing due to several advantages such as simplicity, rapid separation, efficiency, economy, flexibility and biocompatibility. Up to date, a range of biotechnological products have been successfully recovered from different sources with high yield using ATPS-based strategy. In view of the important potential contribution of the ATPS in downstream processing, this review article aims to provide latest information about the application of ATPS in the recovery of various biotechnological products in the past 7 years (2010-2017). Apart from that, the challenges as well as the possible future work and outlook of the ATPS-based recovery method have also been presented in this review article.
    Matched MeSH terms: Water/chemistry*
  4. Modification of oil palm fronds lignin by incorporation of m-cresol for improving structural and antioxidant properties
    Sa'don NA, Rahim AA, Ibrahim MNM, Brosse N, Hussin MH
    Int J Biol Macromol, 2017 Nov;104(Pt A):251-260.
    PMID: 28602987 DOI: 10.1016/j.ijbiomac.2017.06.038
    Lignin extracted from oil palm fronds (OPF) underwent chemical modification by incorporating m-cresol into the lignin matrix. This study reports on the physicochemical properties and antioxidant activity of unmodified autohydrolyzed ethanol organosolv lignin (AH EOL) and the modified autohydrolyzed ethanol organosolv lignin (AHC EOL). The lignin samples were analyzed by FTIR, 1H and 13C NMR spectroscopy, 2D NMR: HSQC spectroscopy, CHN analysis, molecular weight distribution analysis; GPC and thermal analysis; DSC and TGA. The lignin modification has reduced the hydrophobicity of its complex structure by providing better quality lignin with smaller fragments and higher solubility rate in water (DAHCEOL: 42%>DAHEOL: 25%). It was revealed that the modification of lignin has improved their structural and antioxidant properties, thus venture their possible applications.
    Matched MeSH terms: Water/chemistry
  5. Chemically crosslinked hydrogel and its driving force towards superabsorbent behaviour
    Salleh KM, Zakaria S, Sajab MS, Gan S, Chia CH, Jaafar SNS, et al.
    Int J Biol Macromol, 2018 Oct 15;118(Pt B):1422-1430.
    PMID: 29964115 DOI: 10.1016/j.ijbiomac.2018.06.159
    Dissolved oil palm empty fruit bunch (EFB) cellulose in NaOH/urea solvent was mixed with sodium carboxymethylcellulose (NaCMC) to form a green regenerated superabsorbent hydrogel. The effect of concentration of epichlorohydrin (ECH) as the crosslinker on the formation, physical, and chemical properties of hydrogel was studied. Rapid formation and higher gel content of hydrogel were observed at 10% concentration of ECH. The superabsorbent hydrogel was successfully fabricated in this study with the swelling ability >100,000%. Hydrogel with higher concentration of ECH showed opposite trend by having higher superabsorbent property than that of lower concentration. The covalent bond of COC was observed with Attenuated total reflectance fourier transform infrared (ATR-FT-IR) spectroscopy to confirm the occurrence of crosslinking. The physical and chemical properties of hydrogel were affected by swelling phenomenon. Hydrogel with higher degree of swelling exhibited lower moisture retention and higher transparency. Moreover, the weight of the superabsorbent hydrogel increased with the decrement of pH value of external media (distilled water). This study provided substantial information on the effect of different percentage of ECH as crosslinker on hydrogel basic properties. Furthermore, this study affords correlation of many essential driving forces that affected hydrogel superabsorbent property.
    Matched MeSH terms: Water/chemistry
  6. Arginine Complexes with Simvastatin: Apparent Solubility, In Vitro Dissolution and Solid State Characterization
    Affandi MMRMM, Tripathy M, Majeed ABA
    Curr Drug Deliv, 2018;15(1):77-86.
    PMID: 28322162 DOI: 10.2174/1567201814666170320144259
    BACKGROUND: Categorized as a Biopharmaceutics Classification System (BCS) Class II drugs, statin exhibit low aqueous solubility and bioavailability thus presenting an obstacle and great challenge to formulation researchers. This paper describes a de novo approach to enhance the aqueous solubility of one of the most commonly prescribed statins i.e., simvastatin (SMV) by forming a complex (SMV-ARG) with cosolute arginine (ARG).

    METHODS: The complex has been characterized for its apparent solubility and in vitro dissolution. The solid state characterization has been carried out using Fourier Transform Infra-Red (FTIR) Spectroscopy, Elemental Analysis, X-Ray Powder Diffraction (XRD), Differential Scanning Calorimetry (DSC) analysis, Thermal Gravimetric Analysis (TGA) and Scanning Electron Microscopy (SEM).

    RESULTS: Simvastatin-Arginine (SMV-ARG) complex exhibited massive solubility enhancement by 12,000 fold and significant improvement in both acidic and alkaline dissolution media. A conversion of coherent crystalline to non-coherent pattern, and certain extent of amorphization in SMV-ARG complex, fully justifies the enhanced solubility, and hence the dissolution profile.

    CONCLUSION: The present study provides a significant evidence that ARG molecules are capable to form a complex with small molecules and increase their aqueous solubility which prove to be beneficial in drug formulation and development.

    Matched MeSH terms: Water/chemistry
  7. Fulltext Improving Water Permeability of Hydrophilic PVDF Membrane Prepared via Blending with Organic and Inorganic Additives for Humic Acid Separation
    Arahman N, Mulyati S, Fahrina A, Muchtar S, Yusuf M, Takagi R, et al.
    Molecules, 2019 Nov 13;24(22).
    PMID: 31766222 DOI: 10.3390/molecules24224099
    The removal of impurities from water or wastewater by the membrane filtration process has become more reliable due to good hydraulic performance and high permeate quality. The filterability of the membrane can be improved by having a material with a specific pore structure and good hydrophilic properties. This work aims at preparing a polyvinylidene fluoride (PVDF) membrane incorporated with phospholipid in the form of a 2-methacryloyloxyethyl phosphorylcholine, polymeric additive in the form of polyvinylpyrrolidone, and its combination with inorganic nanosilica from a renewable source derived from bagasse. The resulting membrane morphologies were analyzed by using scanning electron microscopy. Furthermore, atomic force microscopy was performed to analyze the membrane surface roughness. The chemical compositions of the resulting membranes were identified using Fourier transform infrared. A lab-scale cross-flow filtration system module was used to evaluate the membrane's hydraulic and separation performance by the filtration of humic acid (HA) solution as the model contaminant. Results showed that the additives improved the membrane surface hydrophilicity. All modified membranes also showed up to five times higher water permeability than the pristine PVDF, thanks to the improved structure. Additionally, all membrane samples showed HA rejections of 75-90%.
    Matched MeSH terms: Water/chemistry*
  8. Fulltext Large-scale structure formation in ionic solution and its role in electrolysis and conductivity
    Yee CN, Ooi CHR, Tan LP, Misran M, Tang NT
    PLoS One, 2019;14(3):e0213697.
    PMID: 30913207 DOI: 10.1371/journal.pone.0213697
    That water may not be an inert medium was indicated by the presence at water's interfaces a negatively charged solute free zone of several hundred microns in thickness called the exclusion zone (EZ). Further evidence was demonstrated by Ovchinnikova's experiments (2009) showing that water can store and release substantial amount of charge. We demonstrate that the charge storage capacity of water arises from highly stable large-scale ionic structures with measurable charge imbalances and discrete levels of charge density. We also show evidence that the charge zones formation requires ionic solutes, and their formation correlate to large change in conductivity, by as much as 250%. Our experiments indicate that large-scale structuring plays a pivotal role in electrolysis and conductivity in ionic solution. We propose that water is an electrochemically active medium and present a new model of electrolysis and conductivity in ionic solution.
    Matched MeSH terms: Water/chemistry
  9. Effect of diacylglycerol interfacial crystallization on the physical stability of water-in-oil emulsions
    Yang J, Qiu C, Li G, Lee WJ, Tan CP, Lai OM, et al.
    Food Chem, 2020 Oct 15;327:127014.
    PMID: 32434126 DOI: 10.1016/j.foodchem.2020.127014
    The influence of diacylglycerol (DAG) combined with polyglycerol polyricinoleate (PGPR) on the stability of water-in-oil (W/O) emulsions containing hydrogenated palm oil (HPO) was studied. Polarized light microscope revealed that DAG promoted HPO to crystallize at the water-oil interface, providing the combination of Pickering and network stabilization effects. It was proposed that the molecular compatibility of fatty acids in DAG with HPO accounted for the promotional effect. The interfacial crystallization of DAG together with the surface activity of PGPR led to the formation of emulsions with uniform small droplets and high freeze-thaw stability. Further exploration of physical properties indicated that the combination of DAG and PGPR dramatically improved the emulsion's viscoelasticity and obtained a larger deformation yield. Water droplets in DAG-based emulsions acted as active fillers to improve the network rigidity. Therefore, DAG is a promising material to be used as emulsifier to enhance the physical stability of W/O emulsions.
    Matched MeSH terms: Water/chemistry
  10. Tailored rigidity of W/O Pickering emulsions using diacylglycerol-based surface-active solid lipid nanoparticles
    Li G, Lee WJ, Tan CP, Lai OM, Wang Y, Qiu C
    Food Funct, 2021 Nov 29;12(23):11732-11746.
    PMID: 34698749 DOI: 10.1039/d1fo01883c
    Pickering water-in-oil (W/O) emulsions were fabricated by using medium-long chain diacylglycerol (MLCD)-based solid lipid nanoparticles (SLNs) and the connection between the characteristics of the SLNs and the colloidal stability of the emulsions was established. Via melt-emulsification and ultrasonication, MLCD-based SLNs with particle sizes of 120-300 nm were obtained with or without other surfactants. The particle size of the SLNs was influenced by the chemical properties of the surfactants, and surfactants decreased the contact angle of SLNs at the oil-water interface. Gelation was observed in SLNs modified by sodium stearoyl lactylate and lecithin, whereas the addition of Tween 20 resulted in a homogeneous SLN solution. The adsorption of surfactants onto SLN surfaces caused the production of higher amounts of α crystals accompanied by delayed crystallization onset which contributed to the reduction of particle size, interfacial tension and oil wetting ability. The W/O emulsions with higher rigidity and physical stability can be obtained by varying surfactant types and by increasing SLN mass ratios to 60%, whereby more SLNs are adsorbed at the droplet surface as a Pickering stabilizer. This study provides useful insights for the development of diacylglycerol-based SLNs and Pickering W/O emulsions which have great potential for food, cosmetic and pharmaceutical applications.
    Matched MeSH terms: Water/chemistry
  11. Impact of sublethal phenol in freshwater fish Labeo rohita on biochemical and haematological parameters
    Muthukumaravel K, Priyadharshini M, Kanagavalli V, Vasanthi N, Ahmed MS, Musthafa MS, et al.
    Environ Monit Assess, 2022 Oct 21;195(1):10.
    PMID: 36269455 DOI: 10.1007/s10661-022-10554-2
    Phenol, an aromatic chemical commonly found in domestic and industrial effluents, upon its introduction into aquatic ecosystems adversely affects the indigenous biota, the invertebrates and the vertebrates. With the increased demand for agrochemicals, a large amount of phenol is released directly into the environment as a byproduct. Phenol and its derivatives tend to persist in the environment for longer periods which in turn poses a threat to both humans and the aquatic ecosystem. In our current study, the response of Labeo rohita to sublethal concentrations of phenol was observed and the results did show a regular decrease in biochemical constituents of the targeted organs. Exposure of Labeo rohita to sublethal concentration of phenol (22.32 mg/L) for an epoch of 7, 21 and 28 days shows a decline in lipid, protein, carbohydrate content and phosphatase activity in target organs such as the gills, muscle, intestine, liver and kidney of the fish. The present study also aims to investigate the toxic effects of phenol with special reference to the haematological parameters of Labeo rohita. At the end of the exposure period, the blood of the fish was collected by cutting the caudal peduncle with a surgical scalpel. And it was observed that the red blood corpuscle count (RBC), white blood corpuscle (WBC), haemoglobin count (Hb), packed cell volume (PCV), mean corpuscular volume (MCV), mean corpuscular haemoglobin (MCH) and mean corpuscular haemoglobin concentration (MCHC) values showed a decline after exposure to phenol for 7 days, while white blood corpuscle (WBC) shows an increased count. At 21 days and 28 days, all the haematological parameters showed a significant decrease.
    Matched MeSH terms: Fresh Water/chemistry
  12. DNAzyme Based Amplified Biosensor on Ultrasensitive Fluorescence Detection of Pb (II) Ions from Aqueous System
    Ravikumar A, Panneerselvam P, Radhakrishnan K, Morad N, Anuradha CD, Sivanesan S
    J Fluoresc, 2017 Nov;27(6):2101-2109.
    PMID: 28819702 DOI: 10.1007/s10895-017-2149-4
    A label -free DNAzyme amplified biosensor is found to be highly selective and sensitive towards fluorescent detection of Pb2+ ions in aqueous media. The DNAzyme complex has designed by the hybridization of the enzyme and substrate strand. In the presence of Pb2+, the DNAzyme activated and cleaved the substrate strand of RNA site (rA) into two oligonucleotide fragments. Further, the free fragment was hybridized with a complementary strand on the surface of MBs. After magnetic separation, SYBER Green I was added and readily intercalate with the dsDNA to gives a bright fluorescence signal with intensity directly proportional to the concentration of Pb2+ions. A detection limit of 5 nM in Pb2+ the detection range 0 to 500 nM was obtained. This label- free fluorescent biosensor has been successfully applied to the determination of environmental water samples. Then results open up the possibility for real-time quantitative detection of Pb2+ with convenient potential applications in the biological and environmental field. Graphical Abstract.
    Matched MeSH terms: Water/chemistry*
  13. Properties of cellulose nanocrystals from oil palm trunk isolated by total chlorine free method
    Lamaming J, Hashim R, Leh CP, Sulaiman O
    Carbohydr Polym, 2017 Jan 20;156:409-416.
    PMID: 27842840 DOI: 10.1016/j.carbpol.2016.09.053
    Cellulose nanocrystals were isolated from oil palm trunk by total chlorine free method. The samples were either water pre-hydrolyzed or non-water pre-hydrolyzed, subjected to soda pulping, acidified and ozone bleached. Cellulose and cellulose nanocrystal (CNC) physical, chemical, thermal properties, and crystallinity index were investigated by composition analysis, scanning electron microscopy, transmission electron microscopy, fourier transform infrared, thermogravimetric analysis and X-ray diffraction. Water pre-hydrolysis reduced lignin (<0.5%) and increased holocellulose (99.6%) of ozone-bleached cellulose. Water pre-hydrolyzed cellulose exhibited surface fibrillation and peeling off after acid hydrolysis process compared to non-fibrillated of non-water pre-hydrolyzed cellulose. Water pre-hydrolysis improved final CNC crystallinity (up to 75%) compared to CNC without water pre-hydrolysis crystallinity (69%). Cellulose degradation was found to occur during ozone bleaching stage but CNC showed an increase in crystallinity after acid hydrolysis. Thus, oil palm trunk CNC can be potentially applied in pharmaceutical, food, medical and nanocomposites.
    Matched MeSH terms: Water/chemistry
  14. Poly-(MMA-IL) filter paper: A new class of paper-based analytical device for thin-film microextraction of multi-class antibiotics in environmental water samples using LC-MS/MS analysis
    Shahriman MS, Mohamad S, Mohamad Zain NN, Raoov M
    Talanta, 2023 Mar 01;254:124188.
    PMID: 36521327 DOI: 10.1016/j.talanta.2022.124188
    A paper-based polymeric ionic liquid (p-Poly-(MMA-IL)) was successfully developed by grafting the polymeric ionic liquid on the surface of commercial filter paper (FP) by using the dipping method, presenting a new cost-effective film. The newly developed p-Poly-(MMA-IL) FP was then applied as a paper-based thin-film microextraction (p-TFME) analytical device to extract 14 compounds as representative of five groups of antibiotic drugs, which were sulfonamides, tetracyclines, fluoroquinolones, penicillin and macrolides in environmental water samples. Besides, p-Poly-(MMA-IL) FP, p-Poly-(MMA) FP, and unmodified filter paper were successfully characterised by FTIR, NMR, FESEM, TGA, and XRD techniques. They underwent significant parameters optimisation, which affected the extraction efficiency. Under optimal conditions, the proposed (p-Poly-(MMA-IL) FP-TFME) device method was evaluated and applied to analyse multi-class antibiotic drugs in environmental water samples by using a liquid chromatography-mass spectrometry (LC-MS). The validation method showed that a good linearity (0.1 μg L-1 - 500 μg L-1) was noted (R2 > 0.993, n = 3). Detection and quantification limits were within 0.05 μg L-1 - 4.52 μg L-1 and 0.15 μg L-1 - 13.6 μg L-1, respectively. The relative standard deviation (RSD) values ranged at 1.4%-12.2% (intra-day, n = 15) and 4.4%-11.0% (inter-day, n = 10). The extraction recoveries of environmental water samples ranged from 79.1% to 126.8%, with an RSD of less than 15.4% (n = 3). The newly developed paper-based polymeric ionic liquid (p-Poly-(MMA-IL) FP) for analysis of multi-class antibiotic drugs under the p-TFME analytical device procedure was successfully achieved with limited sample volume and organic solvent, fast extraction, and feasible in daily analysis. The detection concentration and relative RSD of multi-class antibiotics determined in various environmental water samples by the proposed method (n = 5) were within 0.44 μg L-1 - 54.41 μg L-1 and 0.69%-15.56%, respectively. These results signified the potential of the p-Poly-(MMA-IL) FP-TFME device as an efficient, sensitive and environmentally friendly approach for analysing antibiotics.
    Matched MeSH terms: Water/chemistry
  15. Enhancement of simultaneous batik wastewater treatment and electricity generation in photocatalytic fuel cell
    Khalik WF, Ho LN, Ong SA, Voon CH, Wong YS, Yusuf SY, et al.
    Environ Sci Pollut Res Int, 2018 Dec;25(35):35164-35175.
    PMID: 30328543 DOI: 10.1007/s11356-018-3414-z
    The objective of this study was to investigate several operating parameters, such as open circuit, different external resistance, pH, supporting electrolyte, and presence of aeration that might enhance the degradation rate as well as electricity generation of batik wastewater in solar photocatalytic fuel cell (PFC). The optimum degradation of batik wastewater was at pH 9 with external resistor 250 Ω. It was observed that open circuit of PFC showed only 17.2 ± 7.5% of removal efficiency, meanwhile the degradation rate of batik wastewater was enhanced to 31.9 ± 15.0% for closed circuit with external resistor 250 Ω. The decolorization of batik wastewater in the absence of photocatalyst due to the absorption of light irradiation by dye molecules and this process was known as photolysis. The degradation of batik wastewater increased as the external resistor value decreased. In addition, the degradation rate of batik wastewater also increased at pH 9 which was 74.4 ± 34.9% and at pH 3, its degradation rate was reduced to 19.4 ± 8.7%. The presence of aeration and sodium chloride as supporting electrolyte in batik wastewater also affected its degradation and electricity generation. The maximum absorbance of wavelength (λmax) of batik wastewater at 535 nm and chemical oxygen demand gradually decreased as increased in irradiation time; however, batik wastewater required prolonged irradiation time to fully degrade and mineralize in PFC system.
    Matched MeSH terms: Waste Water/chemistry
  16. Microalgal biomass production through phycoremediation of fresh market wastewater and potential applications as aquaculture feeds
    Apandi NM, Mohamed RMSR, Al-Gheethi A, Kassim AHM
    Environ Sci Pollut Res Int, 2019 Feb;26(4):3226-3242.
    PMID: 30565116 DOI: 10.1007/s11356-018-3937-3
    Microalgal biomass produced from the phycoremediation of wastewater represents an important protein source, lipids, and natural antioxidants and bioproducts. Therefore, the microalgal biomass and their derived compounds are used in animal and aquaculture feed as well as human nutrition and health products. Many microalgal species have shown promising potential for many bioproducts. However, significant processes to find the optimum quality and quantity of microalgal biomass are still required especially when it is used as a replacement for aquaculture feed. The limitations lie in the selection of microalgal species and their production. The present review discusses the potential generation of bioproducts from microalgal biomass resulting from the phycoremediation of wet market wastewater. The consortium approach in wastewater treatment and the comparison between biomass production and available common feeds for aquaculture were reviewed.
    Matched MeSH terms: Waste Water/chemistry*
  17. Adsorption of methylene blue dye from aqueous solution using low-cost adsorbent: kinetic, isotherm adsorption, and thermodynamic studies
    Al-Asadi ST, Al-Qaim FF, Al-Saedi HFS, Deyab IF, Kamyab H, Chelliapan S
    Environ Monit Assess, 2023 May 16;195(6):676.
    PMID: 37188926 DOI: 10.1007/s10661-023-11334-2
    Fig leaf, an environmentally friendly byproduct of fruit plants, has been used for the first time to treat of methylene blue dye. The fig leaf-activated carbon (FLAC-3) was prepared successfully and used for the adsorption of methylene blue dye (MB). The adsorbent was characterized by Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), scanning electron microscopy (SEM), and the Brunauer-Emmett-Teller (BET). In the present study, initial concentrations, contact time, temperatures, pH solution, FLAC-3 dose, volume solution, and activation agent were investigated. However, the initial concentration of MB was investigated at different concentrations of 20, 40, 80, 120, and 200 mg/L. pH solution was examined at these values: pH3, pH7, pH8, and pH11. Moreover, adsorption temperatures of 20, 30, 40, and 50 °C were considered to investigate how the FLAC-3 works on MB dye removal. The adsorption capacity of FLAC-3 was determined to be 24.75 mg/g for 0.08 g and 41 mg/g for 0.02 g. The adsorption process has followed the Langmuir isotherm model (R2 = 0.9841), where the adsorption created a monolayer covering the surface of the adsorbent. Additionally, it was discovered that the maximum adsorption capacity (Qm) was 41.7 mg/g and the Langmuir affinity constant (KL) was 0.37 L/mg. The FLAC-3, as low-cost adsorbents for methylene blue dye, has shown good cationic dye adsorption performance.
    Matched MeSH terms: Water/chemistry
  18. Fulltext A comprehensive review on the use of algal-bacterial systems for wastewater treatment with emphasis on nutrient and micropollutant removal
    Oruganti RK, Katam K, Show PL, Gadhamshetty V, Upadhyayula VKK, Bhattacharyya D
    Bioengineered, 2022 Apr;13(4):10412-10453.
    PMID: 35441582 DOI: 10.1080/21655979.2022.2056823
    The scarcity of water resources and environmental pollution have highlighted the need for sustainable wastewater treatment. Existing conventional treatment systems are energy-intensive and not always able to meet stringent disposal standards. Recently, algal-bacterial systems have emerged as environmentally friendly sustainable processes for wastewater treatment and resource recovery. The algal-bacterial systems work on the principle of the symbiotic relationship between algae and bacteria. This paper comprehensively discusses the most recent studies on algal-bacterial systems for wastewater treatment, factors affecting the treatment, and aspects of resource recovery from the biomass. The algal-bacterial interaction includes cell-to-cell communication, substrate exchange, and horizontal gene transfer. The quorum sensing (QS) molecules and their effects on algal-bacterial interactions are briefly discussed. The effect of the factors such as pH, temperature, C/N/P ratio, light intensity, and external aeration on the algal-bacterial systems have been discussed. An overview of the modeling aspects of algal-bacterial systems has been provided. The algal-bacterial systems have the potential for removing micropollutants because of the diverse possible interactions between algae-bacteria. The removal mechanisms of micropollutants - sorption, biodegradation, and photodegradation, have been reviewed. The harvesting methods and resource recovery aspects have been presented. The major challenges associated with algal-bacterial systems for real scale implementation and future perspectives have been discussed. Integrating wastewater treatment with the algal biorefinery concept reduces the overall waste component in a wastewater treatment system by converting the biomass into a useful product, resulting in a sustainable system that contributes to the circular bioeconomy.
    Matched MeSH terms: Waste Water/chemistry
  19. Integrating of electrocoagulation process with submerged membrane bioreactor for wastewater treatment under low voltage gradients
    Bani-Melhem K, Elektorowicz M, Tawalbeh M, Al Bsoul A, El Gendy A, Kamyab H, et al.
    Chemosphere, 2023 Oct;339:139693.
    PMID: 37536541 DOI: 10.1016/j.chemosphere.2023.139693
    Treating and reusing wastewater has become an essential aspect of water management worldwide. However, the increase in emerging pollutants such as polycyclic aromatic hydrocarbons (PAHs), which are presented in wastewater from various sources like industry, roads, and household waste, makes their removal difficult due to their low concentration, stability, and ability to combine with other organic substances. Therefore, treating a low load of wastewater is an attractive option. The study aimed to address membrane fouling in the submerged membrane bioreactor (SMBR) used for wastewater treatment. An aluminum electrocoagulation (EC) device was combined with SMBR as a pre-treatment to reduce fouling. The EC-SMBR process was compared with a conventional SMBR without EC, fed with real grey water. To prevent impeding biological growth, low voltage gradients were utilized in the EC deviceThe comparison was conducted over 60 days with constant transmembrane pressure and infinite solid retention time (SRT). In phase I, when the EC device was operated at a low voltage gradient (0.64 V/cm), no significant improvement in the pollutants removal was observed in terms of color, turbidity, and chemical oxygen demand (COD). Nevertheless, during phase II, a voltage gradient of 1.26 V/cm achieved up to 100%, 99.7%, 92%, 94.1%, and 96.5% removals in the EC-SMBR process in comparison with 95.1%, 95.4%, 85%, 91.7% and 74.2% removals in the SMBR process for turbidity, color, COD, ammonia nitrogen (NH3-N), total phosphorus (TP), respectively. SMBR showed better anionic surfactant (AS) removal than EC-SMBR. A voltage gradient of 0.64 V/cm in the EC unit significantly reduced fouling by 23.7%, while 1.26 V/cm showed inconsistent results. Accumulation of Al ions negatively affected membrane performance. Low voltage gradients in EC can control SMBR fouling if Al concentration is controlled. Future research should investigate EC-SMBR with constant membrane flux for large-scale applications, considering energy consumption and operating costs.
    Matched MeSH terms: Water/chemistry
  20. Kinetic evidence for the formation of monocationic N,N'-disubstituted phthalamide in tertiary amine-catalyzed hydrolysis of N-substituted phthalimides
    Sim YL, Ariffin A, Khan MN
    J Org Chem, 2007 Oct 26;72(22):8452-8.
    PMID: 17918997
    A kinetic study on the aqueous cleavage of N-(2-methoxyphenyl)phthalimide (1) and N-(2-hydroxyphenyl)phthalimide (2), under the buffers of N-methylmorpholine, reveals the equilibrium presence of monocationic amide (Ctam) formed due to nucleophilic reactions of N-methylmorpholine with 1 and 2. Pseudo-first-order rate constants for the reactions of water and HO- with Ctam (formed through nucleophilic reaction of N-methylmorpholine with 1) are 4.60 x 10(-5) s-1 and 47.9 M-1 s-1, respectively. But the cleavage of Ctam, formed through nucleophilic reaction of N-methylmorpholine with 2, involves intramolecular general base (2'-O- group of Ctam)-assisted water attack at carbonyl carbon of cationic amide group of Ctam in or before the rate-determining step.
    Matched MeSH terms: Water/chemistry
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