Displaying publications 81 - 100 of 412 in total

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  1. Dzinun H, Othman MHD, Ismail AF
    Chemosphere, 2019 Aug;228:241-248.
    PMID: 31035161 DOI: 10.1016/j.chemosphere.2019.04.118
    Comparison studies in suspension and hybrid photocatalytic membrane reactor (HPMR) system was investigated by using Reactive Black 5 (RB5) as target pollutant under UVA light irradiation. To achieve this aim, hybrid TiO2/clinoptilolite (TCP) photocatalyst powder was prepared by solid-state dispersion (SSD) methods and embedded at the outer layer of dual layer hollow fiber (DLHF) membranes fabricated via single step co-spinning process. TiO2 and CP photocatalyst were also used as control samples. The samples were characterized by Scanning Electron Microscopy (SEM), Energy Dispersion of X-ray (EDX), X-ray diffraction (XRD) and Brunauer-Emmett-Teller (BET) analyses. The result shows that TCP was actively functioned as photocatalyst in suspension system and 86% of RB5 photocatalytic degradation achieved within 60 min; however the additional step is required to separate the catalyst with treated water. In the HPMR system, even though the RB5 photocatalytic degradation exhibits lower efficiency however the rejection of RB5 was achieved up to 95% under UV irradiation due to the properties of photocatalytic membranes. The well dispersed of TCP at the outer layer of DLHF membrane have improved the surface affinity of DL-TCP membrane towards water, exhibit the highest pure water flux of 41.72 L/m2.h compared to DL-TiO2 membrane. In general, CP can help on improving photocatalytic activity of TiO2 in suspension, increased the RB5 removal and the permeability of DLHF membrane in HPMR system as well.
  2. Eguchi A, Isobe T, Ramu K, Tue NM, Sudaryanto A, Devanathan G, et al.
    Chemosphere, 2013 Mar;90(9):2365-71.
    PMID: 23149186 DOI: 10.1016/j.chemosphere.2012.10.027
    In Asian developing countries, large amounts of municipal wastes are dumped into open dumping sites each day without adequate management. This practice may cause several adverse environmental consequences and increase health risks to local communities. These dumping sites are contaminated with many chemicals including brominated flame retardants (BFRs) such as polybrominated diphenyl ethers (PBDEs) and hexabromocyclododecanes (HBCDs). BFRs may be released into the environment through production processes and through the disposal of plastics and electronic wastes that contain them. The purpose of this study was to elucidate the status of BFR pollution in municipal waste dumping sites in Asian developing countries. Soil samples were collected from six open waste dumping sites and five reference sites in Cambodia, India, Indonesia, Malaysia, and Vietnam from 1999 to 2007. The results suggest that PBDEs are the dominant contaminants in the dumping sites in Asian developing countries, whereas HBCD contamination remains low. Concentrations of PBDEs and HBCDs ranged from ND to 180 μg/kg dry wt and ND to 1.4 μg/kg dry wt, respectively, in the reference sites and from 0.20 to 430 μg/kg dry wt and ND to 2.5 μg/kg dry wt, respectively, in the dumping sites. Contamination levels of PBDEs in Asian municipal dumping sites were comparable with those reported from electronic waste dismantling areas in Pearl River delta, China.
  3. El-Sheikh MA, Hadibarata T, Yuniarto A, Sathishkumar P, Abdel-Salam EM, Alatar AA
    Chemosphere, 2020 Nov 04.
    PMID: 33220978 DOI: 10.1016/j.chemosphere.2020.128873
    Since a few centuries ago, organochlorine compounds (OCs) become one of the threatened contaminants in the world. Due to the lipophilic and hydrophobic properties, OCs always discover in fat or lipid layers through bioaccumulation and biomagnification. The OCs are able to retain in soil, sediment and water for long time as it is volatile, OCs will evaporate from soil and condense in water easily and frequently, which pollute the shelter of aquatic life and it affects the function of organs and damage system in human body. Photocatalysis that employs the usage of semiconductor nanophotocatalyst and solar energy can be the possible alternative for current conventional water remediation technologies. With the benefits of utilizing renewable energy, no production of harmful by-products and easy operation, degradation of organic pollutants in rural water bodies can be established. Besides, nanophotocatalyst that is synthesized with nanotechnology outnumbered conventional catalyst with larger surface area to volume ratio, thus higher photocatalytic activity is observed. In contrast, disadvantages particularly no residual effect in water distribution network, requirement of post-treatment and easily affected by various factors accompanied with photocatalysis method cannot be ignored. These various factors constrained the photocatalytic efficiency via nanocatalysts which causes the full capacity of solar photocatalysis has yet to be put into practice. Therefore, further modifications and research are still required in nanophotocatalysts' synthesis to overcome limitations such as large band gaps and photodecontamination.
  4. Esfandyari Bayat A, Junin R, Derahman MN, Samad AA
    Chemosphere, 2015 Sep;134:7-15.
    PMID: 25889359 DOI: 10.1016/j.chemosphere.2015.03.052
    The impact of ionic strength (from 0.003 to 500mM) and salt type (NaCl vs MgCl2) on transport and retention of titanium dioxide (TiO2) nanoparticles (NPs) in saturated limestone porous media was systematically studied. Vertical columns were packed with limestone grains. The NPs were introduced as a pulse suspended in aqueous solutions and breakthrough curves in the column outlet were generated using an ultraviolent-visible spectrometry. Presence of NaCl and MgCl2 in the suspensions were found to have a significant influence on the electrokinetic properties of the NP aggregates and limestone grains. In NaCl and MgCl2 solutions, the deposition rates of the TiO2-NP aggregates were enhanced with the increase in ionic strength, a trend consistent with traditional Derjaguin-Landau-Verwey-Overbeek (DLVO) theory. Furthermore, the NP aggregates retention increased in the porous media with ionic strength. The presence of salts also caused a considerable delay in the NPs breakthrough time. MgCl2 as compared to NaCl was found to be more effective agent for the deposition and retention of TiO2-NPs. The experimental results followed closely the general trends predicted by the filtration and DLVO calculations. Overall, it was found that TiO2-NP mobility in the limestone porous media depends on ionic strength and salt type.
  5. Fadhila FR, Umar A, Chandren S, Apriandanu DOB, Yulizar Y
    Chemosphere, 2024 Jan 20;352:141215.
    PMID: 38253085 DOI: 10.1016/j.chemosphere.2024.141215
    The use of chemical materials to tackle environmental concerns has undergone significant evolution, particularly in the pursuit of strategies for removing pollutants from wastewater as part of environmental remediation an increasingly crucial research topic. Employing green photocatalysts stands out as an efficient and cost-effective approach, playing a key role in promoting sustainable environmental remediation. This study introduces the modification of zinc oxide with cobalt chromite (CoCr2O4/ZnO) through a green synthesis method employing Basella alba L. leaves extract (BALE). Utilizing various characterization techniques, including FT-IR, UV-Vis DRS, XRD, SEM-EDS, and TEM, key features of ZnO, CoCr2O4, and CoCr2O4/ZnO nanocomposites were identified. The optical band gaps for ZnO, CoCr2O4, and CoCr2O4/ZnO nanocomposites were determined as 3.16, 1.71, and 2.80 eV, respectively, where it was shown that the band gap of the ZnO was reduced significantly. CoCr2O4/ZnO nanocomposites displayed a cubic shape of CoCr2O4 on the surface of ZnO, with a particle size of 23.84 ± 8.08 nm. The photocatalytic activity was assessed through the degradation of malachite green under visible light irradiation, where the CoCr2O4/ZnO nanocomposites exhibited superior photodegradation efficiency at 90.91%, surpassing ZnO alone (57.09%). This improvement in photocatalytic activity is attributed to a reduced band gap energy and a high rate constant value of 9.57 × 10-3 min-1, demonstrating pseudo-first-order reaction kinetics. In summary, this research presents the development of a ZnO-based photocatalyst with exceptional performance, especially in the visible light spectrum, making it a promising candidate for applications in wastewater removal.
  6. Fakhlaei R, Selamat J, Abdull Razis AF, Sukor R, Ahmad S, Khatib A, et al.
    Chemosphere, 2024 Mar 28;356:141736.
    PMID: 38554873 DOI: 10.1016/j.chemosphere.2024.141736
    Since ancient times, honey has been used for medical purposes and the treatment of various disorders. As a high-quality food product, the honey industry is prone to fraud and adulteration. Moreover, limited experimental studies have investigated the impact of adulterated honey consumption using zebrafish as the animal model. The aims of this study were: (1) to calculate the lethal concentration (LC50) of acid-adulterated Apis mellifera honey on embryos, (2) to investigate the effect of pure and acid-adulterated A. mellifera honey on hatching rate (%) and heart rate of zebrafish (embryos and larvae), (3) to elucidate toxicology of selected adulterated honey based on lethal dose (LD50) using adult zebrafish and (4) to screen the metabolites profile of adulterated honey from blood serum of adult zebrafish. The result indicated the LC50 of 31.10 ± 1.63 (mg/ml) for pure A. mellifera honey, while acetic acid demonstrates the lowest LC50 (4.98 ± 0.06 mg/ml) among acid adulterants with the highest mortality rate at 96 hpf. The treatment of zebrafish embryos with adulterated A. mellifera honey significantly (p ≤ 0.05) increased the hatching rate (%) and decreased the heartbeat rate. Acute, prolong-acute, and sub-acute toxicology tests on adult zebrafish were conducted at a concentration of 7% w/w of acid adulterants. Furthermore, the blood serum metabolite profile of adulterated-honey-treated zebrafish was screened by LC-MS/MS analysis and three endogenous metabolites have been revealed: (1) Xanthotoxol or 8-Hydroxypsoralen, (2) 16-Oxoandrostenediol, and (3) 3,5-Dicaffeoyl-4-succinoylquinic acid. These results prove that employed honey adulterants cause mortality that contributes to higher toxicity. Moreover, this study introduces the zebrafish toxicity test as a new promising standard technique for the potential toxicity assessment of acid-adulterated honey in this study and hazardous food adulterants for future studies.
  7. Fang TY, Praveena SM, deBurbure C, Aris AZ, Ismail SN, Rasdi I
    Chemosphere, 2016 Dec;165:358-368.
    PMID: 27665296 DOI: 10.1016/j.chemosphere.2016.09.051
    In recent years, environmental concerns over ultra-trace levels of steroid estrogens concentrations in water samples have increased because of their adverse effects on human and animal life. Special attention to the analytical techniques used to quantify steroid estrogens in water samples is therefore increasingly important. The objective of this review was to present an overview of both instrumental and non-instrumental analytical techniques available for the determination of steroid estrogens in water samples, evidencing their respective potential advantages and limitations using the Need, Approach, Benefit, and Competition (NABC) approach. The analytical techniques highlighted in this review were instrumental and non-instrumental analytical techniques namely gas chromatography mass spectrometry (GC-MS), liquid chromatography mass spectrometry (LC-MS), enzyme-linked immuno sorbent assay (ELISA), radio immuno assay (RIA), yeast estrogen screen (YES) assay, and human breast cancer cell line proliferation (E-screen) assay. The complexity of water samples and their low estrogenic concentrations necessitates the use of highly sensitive instrumental analytical techniques (GC-MS and LC-MS) and non-instrumental analytical techniques (ELISA, RIA, YES assay and E-screen assay) to quantify steroid estrogens. Both instrumental and non-instrumental analytical techniques have their own advantages and limitations. However, the non-instrumental ELISA analytical techniques, thanks to its lower detection limit and simplicity, its rapidity and cost-effectiveness, currently appears to be the most reliable for determining steroid estrogens in water samples.
  8. Fauzi AA, Jalil AA, Hassan NS, Aziz FFA, Azami MS, Hussain I, et al.
    Chemosphere, 2022 Jan;286(Pt 1):131651.
    PMID: 34346345 DOI: 10.1016/j.chemosphere.2021.131651
    Nanostructured photocatalysts commonly offered opportunities to solve issues scrutinized with the environmental challenges caused by steep population growth and rapid urbanization. This photocatalyst is a controllable characteristic, which can provide humans with a clean and sustainable ecosystem. Over the last decades, one of the current thriving research focuses on visible-light-driven CeO2-based photocatalysts due to their superior characteristics, including unique fluorite-type structure, rigid framework, and facile reducing oxidizing properties of cerium's tetravalent (Ce4+) and trivalent (Ce3+) valence states. Notwithstanding, owing to its inherent wide energy gap, the solar energy utilization efficiency is low, which limits its application in wastewater treatment. Numerous modifications of CeO2 have been employed to enhance photodegradation performances, such as metals and non-metals doping, adding support materials, and coupling with another semiconductor. Besides, all these doping will form a different heterojunction and show a different way of electron-hole migration. Compared to conventional heterojunction, advanced heterojunction types such as p-n heterojunction, Z-scheme, Schottky junction, and surface plasmon resonance effect exhibit superior performance for degradation owing to their excellent charge carrier separation, and the reaction occurs at a relatively higher redox potential. This review attends to providing deep insights on heterojunction mechanisms and the latest progress on photodegradation of various contaminants in wastewater using CeO2-based photocatalysts. Hence, making the CeO2 photocatalyst more foresee and promising to further development and research.
  9. Foo ML, Ooi CW, Tan KW, Chew IML
    Chemosphere, 2022 Jan;287(Pt 2):132108.
    PMID: 34509022 DOI: 10.1016/j.chemosphere.2021.132108
    The groundbreaking innovation and industrialization are ushering in a new era where technology development is integrated with the sustainability of materials. Over the decade, nanocrystalline cellulose (NCC) obtained from lignocellulosic biomass had created a great value in various aspects. The abundantly available empty fruit bunch (EFB) in the palm oil industry has motivated us to utilize it as a sustainable alternative for the isolation of NCC, which is a worthwhile opportunity to the waste management of EFB. Taking advantage of the shape anisotropy and amphiphilic character, NCC has been demonstrated as a natural stabilizer for oil-in-water emulsion. In this work, preparation of highly stable Pickering nanoemulsion using black cumin seed oil and NCC was attempted. Black cumin seed oil is a class of plant oil with various nutritional and pharmaceutical benefits. However, its poor solubility could substantially lower the therapeutic effect, and thus, requires a delivery system to overcome this limitation. The role of NCC in the formation of stable Pickering nanoemulsion was investigated. The emulsification process was found crucial to the resulting droplet size, whereas NCC contributed critically to its stabilization. The droplet size obtained from ultrasonication and microfluidization was approximately 400 nm, as examined using transmission electron microscopy. The droplet (oil-to-water = 2:8) has long-term stability against creaming and coalescence for more than six months. The nanoemulsion stabilized by NCC could allow a better absorption by the human body, thereby maximizing the potential of black cumin seed oil in the personal care and food industries.
  10. Fu D, Kurniawan TA, Avtar R, Xu P, Othman MHD
    Chemosphere, 2021 May;271:129861.
    PMID: 33736203 DOI: 10.1016/j.chemosphere.2021.129861
    This work incorporated technological values into Zn2Cr-layered double hydroxide (LDH), synthesized from unused resources, for removal of pyrophosphate (PP) in electroplating wastewater. To adopt a resource recovery for the remediation of the aquatic environment, the Zn2Cr-LDH was fabricated by co-precipitation from concentrated metals of plating waste that remained as industrial by-products from metal finishing processes. To examine its applicability for water treatment, batch experiments were conducted at optimum M2+/M3+, pH, reaction time, and temperature. To understand the adsorption mechanisms of the PP by the adsorbent, the Zn2Cr-LDH was characterized using Brunauer-Emmett-Teller (BET), X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FT-IR), scanning electron microscopy/energy dispersive X-ray spectroscopy (SEM/EDS), transmission electron microscopy (TEM), and X-ray photoelectron spectroscopy (XPS) analyses before and after adsorption treatment. An almost complete PP removal was attained by the Zn2Cr-LDH at optimized conditions: 50 mg/L of PP, 1 g/L of adsorbent, pH 6, and 6 h of reaction. Ion exchange controlled the PP removal by the adsorbent at acidic conditions. The PP removal well fitted a pseudo-second-order kinetics and/or the Langmuir isotherm model with 79 mg/g of PP adsorption capacity. The spent Zn2Cr-LDH was regenerated with NaOH with 86% of efficiency for the first cycle. The treated effluents could comply with the discharge limit of <1 mg/L. Overall, the use of the Zn2Cr-LDH as a low-cost adsorbent for wastewater treatment has contributed to national policy that promotes a zero-waste approach for a circular economy (CE) through a resource recovery paradigm.
  11. Gan HM, Shahir S, Ibrahim Z, Yahya A
    Chemosphere, 2011 Jan;82(4):507-13.
    PMID: 21094980 DOI: 10.1016/j.chemosphere.2010.10.094
    A co-culture consisting of Hydrogenophaga sp. PBC and Ralstonia sp. PBA, isolated from textile wastewater treatment plant could tolerate up to 100 mM 4-aminobenzenesulfonate (4-ABS) and utilize it as sole carbon, nitrogen and sulfur source under aerobic condition. The biodegradation of 4-ABS resulted in the release of nitrogen and sulfur in the form of ammonium and sulfate respectively. Ninety-eight percent removal of chemical oxygen demand attributed to 20 mM of 4-ABS in cell-free supernatant could be achieved after 118 h. Effective biodegradation of 4-ABS occurred at pH ranging from 6 to 8. During batch culture with 4-ABS as sole carbon and nitrogen source, the ratio of strain PBA to PBC was dynamic and a critical concentration of strain PBA has to be reached in order to enable effective biodegradation of 4-ABS. Haldane inhibition model was used to fit the degradation rate at different initial concentrations and the parameters μ(max), K(s) and K(i) were determined to be 0.13 h⁻¹, 1.3 mM and 42 mM respectively. HPLC analyses revealed traced accumulation of 4-sulfocatechol and at least four unidentified metabolites during biodegradation. This is the first study to report on the characterization of 4-ABS-degrading bacterial consortium that was isolated from textile wastewater treatment plant.
  12. Ganesan S, Vadivelu VM
    Chemosphere, 2019 May;223:668-674.
    PMID: 30802832 DOI: 10.1016/j.chemosphere.2019.02.104
    Hydrazine is an intermediate product of the anaerobic ammonium oxidation (Anammox) process where both ammonium and nitrite in wastewater are converted to nitrogen gas by bacteria. In this study the effect of external hydrazine addition (5, 10, 15, and 20 mg/L) on the start-up period of the Anammox process was studied using sequencing batch reactors (SBRs). The SBR with an addition of 10 mg/L hydrazine took only 7 weeks to stabilize and achieve the maximum removal of ammonium and nitrite, whereas the SBR without the addition of hydrazine took 12 weeks. The amount of Heme C extracted from the biomass indicated that externally added hydrazine accelerated the growth of Anammox bacteria and reduced the release of nitrous oxide gas from the reactors.
  13. Gasim MF, Lim JW, Low SC, Lin KA, Oh WD
    Chemosphere, 2022 Jan;287(Pt 4):132458.
    PMID: 34610377 DOI: 10.1016/j.chemosphere.2021.132458
    Over the past decade, there has been a surge of interest in using char (hydrochar or biochar) derived from biomass as persulfate (PS, either peroxymonosulfate or peroxydisulfate) activator for anthropogenic pollutants removal. While extensive investigation showed that char could be used as a PS activator, its sustainability over prolonged application is equivocal. This review provides an assessment of the knowledge gap related to the sustainability of char as a PS activator. The desirable char properties for PS activation are identified, include the high specific surface area and favorable surface chemistry. Various synthesis strategies to obtain the desirable properties during biomass pre-treatment, hydrochar and biochar synthesis, and char post-treatment are discussed. Thereafter, factors related to the sustainability of employing char as a PS activator for anthropogenic pollutants removal are critically evaluated. Among the critical factors include performance uncertainty, competing adsorption process, char stability during PS activation, biomass precursor variation, scalability, and toxic components in char. Finally, some potential research directions are provided. Fulfilling the sustainability factors will provide opportunity to employ char as an economical and efficient catalyst for sustainable environmental remediation.
  14. Gayathiri M, Pulingam T, Lee KT, Sudesh K
    Chemosphere, 2022 Jan 28;294:133764.
    PMID: 35093418 DOI: 10.1016/j.chemosphere.2022.133764
    The use of activated carbon is evidenced by the increased scope of carbon-based applications in various industrial applications including pharmaceutical antidotes, wastewater remediation, aquaculture and toxin removal. Activated carbon produced from biomass waste by various processing methods and conditions is emerging as a promising adsorbent for remediation of the ecosystem due to extensive discharge of pollutants. Methods of producing activated carbon, nature of lignocellulosic biomass waste, and interaction of adsorbent-adsorbate are some of the crucial factors that need to be scrutinized to produce an effective adsorbent. However, these factors have not been thoroughly discussed in the literature. Activated carbon needs to go through continuous and rigorous research and development through optimization of key parameters such as type of activation (physical/chemical) and processing conditions, especially for large-scale production. It is imperative to have a detailed understanding of the preeminent characteristics of the activated carbon such as pore size distribution, total pore volume, surface area, and yield of activated carbon that control the extents of adsorptions and production of activated carbon. To further clarify the involved mechanism, studies should focus on all the possible variables that influence the system. Therefore, this review provides a better understanding of factors that affect the production of an efficient activated carbon, important properties to be used as an adsorbent, and the involved mechanisms during the adsorption process followed by increasing demand for activated carbon in various fields.
  15. Gebretatios AG, Kadiri Kanakka Pillantakath AR, Witoon T, Lim JW, Banat F, Cheng CK
    Chemosphere, 2023 Jan;310:136843.
    PMID: 36243081 DOI: 10.1016/j.chemosphere.2022.136843
    Following the discovery of Stöber silica, the realm of morphology-controlled mesoporous silica nanomaterials like MCM-41, SBA-15, and KCC-1 has been expanded. Due to their high BET surface area, tunable pores, easiness of functionalization, and excellent thermal and chemical stability, these materials take part a vital role in the advancement of techniques and technologies for tackling the world's largest challenges in the area of water and the environment, energy storage, and biotechnology. Synthesizing these materials with excellent physicochemical properties from cost-efficient biomass wastes is a foremost model of sustainability. Particularly, SiO2 with a purity >98% can be obtained from rice husk (RH), one of the most abundant biomass wastes, and can be template engineered into various forms of mesoporous silica materials in an economic and eco-friendly way. Hence, this review initially gives insight into why to valorize RH into value-added silica materials. Then the thermal, chemical, hydrothermal, and biological methods of high-quality silica extraction from RH and the principles of synthesis of mesoporous and fibrous mesoporous silica materials like SBA-15, MCM-41, MSNs, and KCC-1 are comprehensively discussed. The potential applications of rice husk-derived mesoporous silica materials in catalysis, drug delivery, energy, adsorption, and environmental remediation are explored. Finally, the conclusion and the future outlook are briefly highlighted.
  16. Ghaedi S, Seifpanahi-Shabani K, Sillanpää M
    Chemosphere, 2022 Apr;292:133412.
    PMID: 34974049 DOI: 10.1016/j.chemosphere.2021.133412
    Currently, heavy metals and dyes are some of the most critical pollutants in the aquatic environment. So, in this paper "waste-to-resource conversion", as a new application of modified mine silicate waste to remove Pb2+ ion and methylene blue (MB) dye, adsorption properties, mechanism of action and recycling were studied. Silicate wastes are located in the alteration zone and the margin of molybdenum ore, these wastes are under the influence of hydrothermal solutions which are impregnated with iron and manganese ions. Hence, acid and base modifications have been commonly used. So, in this study, a highly porous nanostructure of modified silicate waste was used to remove MB and Pb2+ ion, in subsequent to our previous study on the application of the raw material of the same in the removal of malachite green. Acid, base, and acid/base treatments were used to activate and modify the adsorbent. Results show a significantly higher potential of modified adsorbent in the removal of MB and Pb2+ compared to the raw material. According to the isotherm and kinetic studies for MB and Pb2+ the Langmuir and Temkin and pseudo-second-order models were investigated with experimental data. Modified nanomaterial was used for several adsorption and desorption processes, without a significant decrease in the capability of the adsorbent in the removal of MB and Pb2+ pollutants. Leached iron and manganese ions (as production of modification) are deposited in the form of sludge using a simple pH adjustment and precipitation process and can be used to recover iron and manganese metals in the long run. The comparison of monolayer adsorption capacity using for Pb2+ ion and MB dye are as ((untreated SW: 29.41, 1.05); (NaOH treated: 21.74, 100); (Nitric Acid treated: 16.67, 142.86); (Citric Acid treated: 40, 125); (Nitric/Citric Acids treated: 15.63, 111.11) and (Nitric/Citric Acids/NaOH treated: 15.15, 83.33)), respectively. Higher adsorption capacity and re-generable properties of this adsorbent suggest the usage of this natural and abundant mine waste to treat wastewater containing toxic elements and dyes.
  17. Ghanem OB, Mutalib MIA, Lévêque JM, El-Harbawi M
    Chemosphere, 2017 Mar;170:242-250.
    PMID: 28006757 DOI: 10.1016/j.chemosphere.2016.12.003
    Ionic liquids (ILs) are class of solvent whose properties can be modified and tuned to meet industrial requirements. However, a high number of potentially available cations and anions leads to an even increasing members of newly-synthesized ionic liquids, adding to the complexity of understanding on their impact on aquatic organisms. Quantitative structure activity∖property relationship (QSAR∖QSPR) technique has been proven to be a useful method for toxicity prediction. In this work,σ-profile descriptors were used to build linear and non-linear QSAR models to predict the ecotoxicities of a wide variety of ILs towards bioluminescent bacterium Vibrio fischeri. Linear model was constructed using five descriptors resulting in high accuracy prediction of 0.906. The model performance and stability were ascertained using k-fold cross validation method. The selected descriptors set from the linear model was then used in multilayer perceptron (MLP) technique to develop the non-linear model, the accuracy of the model was further enhanced achieving high correlation coefficient with the lowest value being 0.961 with the highest mean square error of 0.157.
  18. Ghanem OB, Shah SN, Lévêque JM, Mutalib MIA, El-Harbawi M, Khan AS, et al.
    Chemosphere, 2018 Mar;195:21-28.
    PMID: 29248749 DOI: 10.1016/j.chemosphere.2017.12.018
    Over the past decades, Ionic liquids (ILs) have gained considerable attention from the scientific community in reason of their versatility and performance in many fields. However, they nowadays remain mainly for laboratory scale use. The main barrier hampering their use in a larger scale is their questionable ecological toxicity. This study investigated the effect of hydrophobic and hydrophilic cyclic cation-based ILs against four pathogenic bacteria that infect humans. For that, cations, either of aromatic character (imidazolium or pyridinium) or of non-aromatic nature, (pyrrolidinium or piperidinium), were selected with different alkyl chain lengths and combined with both hydrophilic and hydrophobic anionic moieties. The results clearly demonstrated that introducing of hydrophobic anion namely bis((trifluoromethyl)sulfonyl)amide, [NTF2] and the elongation of the cations substitutions dramatically affect ILs toxicity behaviour. The established toxicity data [50% effective concentration (EC50)] along with similar endpoint collected from previous work against Aeromonas hydrophila were combined to developed quantitative structure-activity relationship (QSAR) model for toxicity prediction. The model was developed and validated in the light of Organization for Economic Co-operation and Development (OECD) guidelines strategy, producing good correlation coefficient R2 of 0.904 and small mean square error (MSE) of 0.095. The reliability of the QSAR model was further determined using k-fold cross validation.
  19. Guan R, Van Le Q, Yang H, Zhang D, Gu H, Yang Y, et al.
    Chemosphere, 2021 May;271:129499.
    PMID: 33445014 DOI: 10.1016/j.chemosphere.2020.129499
    Phytochemicals refer to active substances in plant-based diets. Phytochemicals found in for example fruits, vegetables, grains and seed oils are considered relatively safe for consumption due to mammal-plant co-evolution and adaptation. A number of human diseases are related to oxidative stress caused by for example chemical environmental contaminants in air, water and food; while also lifestyle including smoking and lack of exercise and dietary preferences are important factors for disease development in humans. Here we explore the dietary sources of antioxidant phytochemicals that have beneficial effects on oxidative stress, cardiovascular and neurological diseases as well as cancer. Plant-based diets usually contain phenolic acids, flavonoids and carotenoids, which have strong antioxidant properties, and therefore remove the excess of active oxygen in the body, and protect cells from damage, reducing the risk of cardiovascular and Alzheimer's disease. In most cases, obesity is related to diet and inactivity and plant-based diets change lipid composition and metabolism, which reduce obesity related hazards. Cruciferous and Allium vegetables are rich in organic sulphides that can act on the metabolism of carcinogens and therefore used as anti-cancer and suppressing agents while dietary fibres and plant sterols may improve intestinal health and prevent intestinal diseases. Thus, we recommend a diet rich in fruits, vegetables, and grains as its content of phytochemicals may have the potential to prevent or improve a broad sweep of various diseases.
  20. Hadibarata T, Kristanti RA, Bilal M, Yilmaz M, Sathishkumar P
    Chemosphere, 2023 Jan;312(Pt 1):137260.
    PMID: 36400190 DOI: 10.1016/j.chemosphere.2022.137260
    For decades, most of the developing nations have relied on chlorpyrifos for insecticidal activity in the agriculture sector. It is a common chlorinated organophosphorus pesticide that has been widely used to control insects to protect plants. This study aimed to investigate the effects of environmental characteristics such as salinity, pH, temperature, and surfactant on Hortaea sp. B15 mediated degradation of chlorpyrifos as well as enzyme activity and metabolic pathway. The highest bacterial growth (4.6 × 1016 CFU/mL) was achieved after 20 h of incubation in a 100 mg/L chlorpyrifos amended culture. The fit model and feasible way to express the chlorpyrifos biodegradation kinetics in normal condition and optimized was a first-order rate equation, with an R2 value of 0.95-0.98. The optimum pH for chlorpyrifos biodegradation was pH 9, which resulted in a high removal rate (91.1%) and a maximum total count of 3.8 × 1016 CFU/mL. Increasing the temperature over 40 °C may inhibit microbial development and biodegradation. There was no significant effect of culture salinity on degradation and bacterial growth. In the presence of non-ionic surfactant Tween 80, the maximum chlorpyrifos degradation (89.5%) and bacterial growth (3.8 × 1016 CFU/mL) was achieved. Metabolites such as 3,5,6-trichloropyridin-2-ol and 2-pyridinol were identified in the Hortaea sp. B15 mediated degradation of chlorpyrifos. According to the findings, Hortaea sp. B15 should be recommended for use in the investigation of in situ biodegradation of pesticides.
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