Displaying publications 1 - 20 of 438 in total

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  1. Tay KS, Rahman NA, Abas MR
    Chemosphere, 2010 Dec;81(11):1446-53.
    PMID: 20875662 DOI: 10.1016/j.chemosphere.2010.09.004
    This study investigated the reaction kinetics and degradation mechanism of parabens (methylparaben, ethylparaben, propylparaben and butylparaben) during ozonation. Experiments were performed at pH 2, 6 and 12 to determine the rate constants for the reaction of protonated, undissociated and dissociated paraben with ozone. The rate constants for the reaction of ozone with dissociated parabens (3.3 × 10(9)-4.2 × 10(9)M(-1)s(-1)) were found to be 10(4) times higher than the undissociated parabens (2.5 × 10(5)-4.4 × 10(5)M(-1)s(-1)) and 10(7) times higher than with the protonated parabens (1.02 × 10(2)-1.38 × 10(2)M(-1)s(-1)). The second-order rate constants for the reaction between parabens with hydroxyl radicals were found to vary from 6.8 × 10(9) to 9.2 × 10(9)M(-1)s(-1). Characterization of degradation by-products (DBPs) formed during the ozonation of each selected parabens has been carried out using GCMS after silylation. Twenty DBPs formed during ozonation of selected parabens have been identified. Hydroxylation has been found to be the major reaction for the formation of the identified DBPs. Through the hydroxylation reaction, a variety of hydroxylated parabens was formed.
  2. Tay KS, Rahman NA, Abas MR
    Chemosphere, 2009 Aug;76(9):1296-302.
    PMID: 19570564 DOI: 10.1016/j.chemosphere.2009.06.007
    This study was undertaken in order to understand the factors affecting the degradation of an insect repellent, N,N-diethyl-m-toluamide (DEET) by ozonation. Kinetic studies on DEET degradation were carried out under different operating conditions, such as varied ozone doses, pH values of solution, initial concentrations of DEET, and solution temperatures. The degradation of DEET by ozonation follows the pseudo-first-order kinetic model. The rate of DEET degradation increased exponentially with temperature in the range studied (20-50 degrees C) and in proportion with the dosage of ozone applied. The ozonation of DEET under different pH conditions in the presence of phosphate buffer occurred in two stages. During the first stage, the rate constant, k(obs), increased with increasing pH, whereas in the second stage, the rate constant, k(obs2), increased from pH 2.3 up to 9.9, however, it decreased when the pH value exceeded 9.9. In the case where buffers were not employed, the k(obs) were found to increase exponentially with pH from 2.5 to 9.2 and the ozonation was observed to occur in one stage. The rate of degradation decreased exponentially with the initial concentration of DEET. GC/MS analysis of the by-products from DEET degradation were identified to be N,N-diethyl-formamide, N,N-diethyl-4-methylpent-2-enamide, 4-methylhex-2-enedioic acid, N-ethyl-m-toluamide, N,N-diethyl-o-toluamide, N-acetyl-N-ethyl-m-toluamide, N-acetyl-N-ethyl-m-toluamide 2-(diethylamino)-1-m-tolylethanone and 2-(diethylcarbamoyl)-4-methylhex-2-enedioic acid. These by-products resulted from ozonation of the aliphatic chain as well as the aromatic ring of DEET during the degradation process.
  3. Loo WW, Pang YL, Lim S, Wong KH, Lai CW, Abdullah AZ
    Chemosphere, 2021 Jun;272:129588.
    PMID: 33482519 DOI: 10.1016/j.chemosphere.2021.129588
    Iron-doped titanium dioxide loaded on activated carbon (Fe-TiO2/AC) was successfully synthesized from oil palm empty fruit bunch (OPEFB) using sol-gel method. The properties of the synthesized pure TiO2, Fe-doped TiO2, AC, TiO2/AC and Fe-TiO2/AC were examined by various techniques such as field emission scanning electron microscopy (FE-SEM), Fourier-transform infrared spectroscopy (FT-IR), UV-Vis diffuse reflectance spectroscopy (UV-Vis DRS) and nitrogen adsorption-desorption analyses at 77 K. FE-SEM revealed that Fe-doped TiO2 particles were dispersed homogeneously on the AC surface. FT-IR demonstrated high surface hydroxylation after Fe doping on TiO2 and UV-Vis DRS showed that Fe-TiO2/AC had the lowest band gap energy. Catalytic performance results proved that Fe dopants could restrict the recombination rate of hole and electron pairs, whereas AC support improved the Malachite Green (MG) adsorption sites and active sites of the hybrid catalyst. Photocatalytic degradation of 100 mg/L MG in the presence of 1.0 g/L 15 wt% Fe-TiO2 incorporated with 25 wt% AC, initial solution pH of 4 and 3 mM H2O2 could achieve the highest removal efficiency of 97% after 45 min light irradiation. This work demonstrates a promising approach to synthesis an inexpensive and efficient Fe-TiO2/AC for the photocatalytic degradation of organic dye.
  4. Yogarathinam LT, Velswamy K, Gangasalam A, Ismail AF, Goh PS, Subramaniam MN, et al.
    Chemosphere, 2022 Jan;286(Pt 3):131822.
    PMID: 34416593 DOI: 10.1016/j.chemosphere.2021.131822
    In this study, fouling mechanism and modelling analysis of synthetic lignocellulose biomass and agricultural palm oil effluent was studied using polyethersulfone (PES) ultrafiltration (UF) 10 kDa membrane. The impact of process variables (transmembrane pressure (TMP), pH and concentration of feed solution) on lignocellulosic flux was analysed using pore blocking model. The feasible approaches on utilising deep learning artificial neural network (ANN) to predict smaller flux datasets are studied. Among the input variables, pH of lignin feed solution has significant control towards flux and lignin rejection coefficient for both lignin and lignocellulosic solution. Alteration in the structure of lignin at different pH conditions contributed in the improvement of lignin rejection coefficient to 0.98 at the feed pH of 9. A maximum steady state flux of 52.03 L/m2h was observed at the lower lignin concentration (0.25 g/L), TMP of 200 kPa and feed pH of 3. At high TMP and concentration, lignin rejection decreased due to enhancement of feed concentration on membrane surface. The mechanistic model exhibited that cake layer phenomena was dominant in both lignin and lignocellulosic solution. The proposed ANN model showed good correlation (R2-1.00) with experimental non-linear flux dynamic data of both lignin and synthetic lignocellulosic solution. In ANN analysis, activation function, algorithm and neuron effect have significant effect in design of accurate model for prediction of small flux datasets. Aerobically-treated palm oil mill filtration analysis also showed that cake layer phenomenon was dominant. A water recovery of 82 % was achieved even at low TMP under short durations.
  5. Batool S, Shah AA, Abu Bakar AF, Maah MJ, Abu Bakar NK
    Chemosphere, 2022 Feb;289:133011.
    PMID: 34863732 DOI: 10.1016/j.chemosphere.2021.133011
    Unique zerovalent iron (Fe0) supported on biochar nanocomposite (Fe0-BRtP) was synthesized from Nephelium lappaceum (Rambutan) fruit peel waste and were applied for the simultaneous removal of 6 selected organochlorine pesticides (OCPs) from aqueous medium. During facile synthesis of Fe0-BRtP, Rambutan peel extract was used as the green reducing mediator to reduce Fe2+ to zerovalent iron (Fe0), instead of toxic sodium borohydride which were used for chemical synthesis. For comparison, chemically synthesized Fe0-BChe nanocomposite was also prepared in this work. Characterization study confirmed the successful synthesis and dispersion of Fe0 nanoparticles on biochar surface. Batch experiments revealed that Fe0-BRtP and Fe0-BChe nanocomposites combine the advantage of adsorption and dechlorination of OCPs in aqueous medium and up to 96-99% and 83-91% removal was obtained within 120 and 150 min, respectively at initial pH 4. Nevertheless, the reactivity of Fe0-BChe nanocomposite decreased 2 folds after being aged in air for one month, whilst Fe0-BRtP almost remained the same. Adsorption isotherm of OCPs were fitted well to Langmuir isotherm and then to Freundlich isotherm. The experimental kinetic data were fitted first to pseudo-second-order adsorption kinetic model and then to pseudo-first-order reduction kinetic model. The adsorption mechanism involves π-π electron-donor-acceptor interaction and adsorption is facilitated by the hydrophobic sorption and pore filling. After being reused five times, the removal efficiency of regenerated Fe0-BChe and Fe0-BRtP was 5-13% and 89-92%, respectively. The application of this Fe0-BRtP nanocomposite could represent a green and low-cost potential material for adsorption and subsequent reduction of OCPs in aquatic system.
  6. Ikmal Misnal MF, Redzuan N, Firdaus Zainal MN, Raja Ibrahim RK, Ahmad N, Agun L
    Chemosphere, 2021 Jul;274:129972.
    PMID: 33979941 DOI: 10.1016/j.chemosphere.2021.129972
    Future demand of rice is projected to increase with the increase of global population. However, the presence of bacteria, insects, and fungi has resulted in various changes in the physical and chemical characteristics of rice grain. To make it worse, the overuse of post-harvest chemicals (fungicide and pesticide) has caused possible risks to human health through either occupational or non-occupational exposure. For the last few years, cold plasma has been developed as an alternative non-thermal emerging technology for rice grains treatment due to its ability to inactivate or decontaminate pathogens without causing thermal damage and free of any harmful residues. Therefore, this review describes the operational mechanism of cold plasma treatment technology on rice grains, existing reactor system designs, and parameters influenced by the treatment technology (reactor design parameters and treatment process parameters). Possible advanced investigation on future reactor design modification as well as standard operating range of influenced parameters were suggested for improved efficiency and effectiveness of cold plasma treatment.
  7. Rather SU, Sulaimon AA, Shariff AM, Qasim A, Bamufleh HS, Alhumade HA, et al.
    Chemosphere, 2023 Oct;337:139290.
    PMID: 37348612 DOI: 10.1016/j.chemosphere.2023.139290
    Carbon dioxide is a major greenhouse gas that is responsible for global warming and renders harmful effects on the atmosphere. The unconstrained release of CO2 into the atmosphere should be prevented and various techniques have been developed in this regard to capture CO2 using different solvents and other compounds. Ionic liquids are a suitable candidate to capture CO2 due to their better solubility behaviour. In this work, two ionic liquids namely tetramethylammonium bromide (TMAB) and tetraethylammonium bromide (TEAB) are employed experimentally to capture CO2 and investigate their solubility behaviour. The study is performed at the temperature values of 303 K, 313 K, and 323 K and the pressure values of 5, 10, 15, and 20 bar equivalent to 0.5, 1.0, 1.5, and 2.0 MPa respectively. The concentrations of both ionic liquid solutions are 2.5 wt%, 5.0 wt%, and 10.0 wt%. The solubility results are considered in terms of mol fraction which is the ratio of moles of CO2 captured per moles of ionic liquid. The density and viscosity values are also determined for both compounds at respective conditions. COSMO-RS is used to generate the sigma profile, sigma surface, and Henry's constant of the ions involved in the study. CO2 is found to be soluble in both ionic liquids, but TEAB showed better solubility behaviour as compared to TMAB. The solubility of CO2 is found to be increasing with the increase in pressure while it decreases with the increase in temperature.
  8. Roslee NF, Kamil NAFM, Alias S, Senthil Kumar P, Alkhadher S, Muthusamy G, et al.
    Chemosphere, 2023 Sep;334:139037.
    PMID: 37244559 DOI: 10.1016/j.chemosphere.2023.139037
    Palm oil fuel ash (POFA) has limited use as a fertilizer, while contribute effectively to the environmental contamination and health risks. Petroleum sludge poses a serious effect on the ecological environment and human health. The present work aimed to present a novel encapsulation process with POFA binder for treating petroleum sludge. Among 16 polycyclic aromatic hydrocarbons, four compounds were selected for the optimization of encapsulation process due to their high risk as carcinogenic substrates. Percentage PS (10-50%) and curing days (7-28 days) factors were used in the optimization process. The leaching test of PAHs was assessed using a GC-MS. The best operating parameters to minimize PAHs leaching from solidified cubes with OPC and10% POFA were recorded with 10% PS and after 28 days, at which PAH leaching was 4.255 and 0.388 ppm with R2 is 0.90%. Sensitivity analysis of the actual and predicted results for both the control and the test (OPC and 10% POFA) revealed that the actual results of the 10% POFA experiments have a high consistency with the predicted data (R2 0.9881) while R2 in the cement experiments was 0.8009. These differences were explained based on the responses of PAH leaching toward percentage of PS and days of cure. In the OPC encapsulation process, the main role was belonged to PS% (94.22%), while with 10% POFA, PS% contributed by 32.36 and cure day contributed by 66.91%.
  9. Al-Gheethi AA, Azhar QM, Senthil Kumar P, Yusuf AA, Al-Buriahi AK, Radin Mohamed RMS, et al.
    Chemosphere, 2022 Jan;287(Pt 2):132080.
    PMID: 34509011 DOI: 10.1016/j.chemosphere.2021.132080
    Rhodamine B (RhB) is among the toxic dyes due to the carcinogenic, neurotoxic effects and ability to cause several diseases for humans. The adsorption with agricultural waste adsorbent recorded high performance for the RhB removal. The current review aimed to explore the efficiency of different adsorbents which have been used in the few last years for removing RhB dye from wastewater. The data of adsorption of RhB using agricultural wastes were collected from the Scopus database in the period between 2015 and 2021. The use of agricultural wastes and adsorbents as a replacement for the activated has received high attention among researchers. The RhB removal methods by microbial enzymes and biomass occurred between 76 and 90.1%. In comparison, the adsorption with agricultural wastes such as activated carbon white sugar reached 98% within 12 min. The adsorption process has a wide range of pH (3-10) due to the zwitterionic forms of RhB. Gmelina aborea leaf activated carbon is among the agriculture wastes absorbents that exhibited 1000 mg g-1 of the adsorption capacity. It appeared that the agricultural wastes adsorbents have a high potential for removing RhB from the wastewater.
  10. Hai T, Ali MA, Alizadeh A, Almojil SF, Almohana AI, Alali AF
    Chemosphere, 2023 Apr;319:137847.
    PMID: 36657576 DOI: 10.1016/j.chemosphere.2023.137847
    Renewable energy sources are undoubtedly necessary, considering global electricity demand is expected to rise dramatically in the coming years. This research looks at a unique multi-generation plant from the perspectives of exergy, energy, and economics; also, an environmental evaluation is performed to estimate the systems' CO2 emissions. The unit is made up of a biomass digester and gasifier, a Multi effect Desalination unit, and a supercritical CO2 (SCO2) cycle. In this study, two methods for using biomass are considered: the first is using synthesis gas generated by the gasifier, and the second is utilizing a digester to generate biogas. A comprehensive parametric study is performed on the designed energy unit to assess the influence of compressor pressure ratio, Gas turbine inlet temperature, supercritical CO2 cycle pressure ratio, and the number of effects of multi-effect distillation on the system performance. Furthermore, the exergy study revealed that the exergy destruction in the digestion unit was 11,337 kW, which was greater than the exergy destruction in the gasification unit, which was 9629. Finally, when compared to the gasifier, the amount of exergy efficiency, net output power, and freshwater production in the digester was greater.
  11. Qutob M, Rafatullah M, Muhammad SA, Siddiqui MR, Alam M
    Chemosphere, 2024 Sep 06;364:143291.
    PMID: 39243904 DOI: 10.1016/j.chemosphere.2024.143291
    Nature iron is considered one of the promising catalysts in advanced oxidation processes (AOPs) that are utilized for soil remediation from polycyclic aromatic hydrocarbons (PAHs). However, the existence of anions, cations, and organic matter in soils considered impurities that restricted the utilization of iron that was harnessed naturally in the soil matrix and reduced the catalytic performance. In this regard, tropical soil naturally containing iron and relatively poor with impurities was artificially contaminated with 100 mg/50 g benzo[α]pyrene (B[α]P) and remediated using a slurry phase reactor supported with persulfate (PS). The results indicated that tropical soil containing iron and relatively poor with impurities capable of activating the oxidants and formation of radicals which successfully degraded B[α]P. The optimum removal result was 86% and obtained under the following conditions airflow = 260 mL/min, temperature 55 °C, pH 7, and [PS]0 = 1.0 g/L, at the same experimental conditions soil organic matter (SOM) mineralization was 48%. After the remediation process, there was a significant reduction in iron and aluminum contents, which considered the drawbacks of this system. Experiments to scavenge reactive species highlighted O2•- and SO4•- as the main radicals that oxidized B[α]P. Additionally, monitoring of by-products post-remediation aimed to assess toxicity and elucidate degradation pathways. Mutagenicity tests yielded positive results for two B[α]P by-products. The toxicity tests considered were the lethal concentration of 50% (LC50 96 h) for fat-head minnows revealed that all B[α]P by-products were less toxic than the parent pollutant itself. This research marks a significant advancement in soil remediation by advancing the use of the AOP method, removing the requirement for additional catalysts in the AOP system for the removal of B[α]P from soil.
  12. Hai T, Alsubai S, Yahya RO, Gemeay E, Sharma K, Alqahtani A, et al.
    Chemosphere, 2023 Oct;338:139371.
    PMID: 37442387 DOI: 10.1016/j.chemosphere.2023.139371
    Combined cooling, heating and power (CCHP) is one of methods for enhancing the efficiency of the energy conversion systems. In this study a CCHP system consisting of a gas turbin (GT) as the topping cycle, and an organic Rankine cycle (ORC) associated with double-effect absorbtion chiller (DEACH) is decisioned as the bottoming cycle to recover the waste heat from GT exhaust gas. The considered CCHP system is investigated to maintain electricity, heating and cooling demand of a town. A parametric study is investigated and the effect decision variables on the performance indicators including exergy efficiency, total cost rate (TCR), cooling capacity, and ORC power generation is examined. Decision variables of the ORC system consist of HRVG pressure, and condenser pressure and the DEACH including evaporator pressure, condseser pressure, concentration of the concentrated solution, concentration of the weak solution, and solution mass flow rate. Finally a multi-objective optimization performed using Genetic Algorithm (GA) and the optimal design point is selected. It is observed at the optimum point the exergy efficiency, TCR, and sustainability index are 17.56%, 74.49 $/h, and 1.21, respectively.
  13. Karim AR, Danish M, Alam MG, Majeed S, Alanazi AM
    Chemosphere, 2024 Mar;351:141180.
    PMID: 38218237 DOI: 10.1016/j.chemosphere.2024.141180
    In contemporary wastewater treatment industry, advanced oxidation techniques, membrane filtration, ion exchange, and reverse osmosis are used to treat chemically loaded wastewater. All these methods required highly toxic oxidizing chemicals, high capital investment in membrane/filter materials, and the installation of sophisticated equipment. Wastewater treatment through an adsorption process using biomass-based adsorbent is economical, user-friendly, and sustainable. Neem tree waste has been explored as an adsorbent for wastewater treatment. The chemical components in the neem biomass include carbohydrates, fat, fiber, cellulose, hemicellulose, and lignin, which support the functionalization of neem biomass. Moreover, adsorbent preparation from renewable resources is not only cost-effective and environmentally friendly but also helps in waste management for sustainable growth. Contemporary researchers explored the pre- and post-surface-modified neem biomass adsorbents in scavenging the pollutants from contaminated water. This review extensively explores the activation process of neem biomass, physical and chemical methods of surface modification mechanism, and the factors affecting surface modification. The pollutant removal through pre and post-surface-modified neem biomass adsorbents was also summarized. Furthermore, it also provides a comprehensive summary of the factors that affect the adsorption performance of the neem biomass-derived adsorbents against dyes, metal ions, and other emerging pollutants. Understanding the surface-modification mechanisms and the adsorption efficiency factor of adsorbents will help in harnessing their potential for more efficiently combatting environmental pollution and making strides toward a greener and more sustainable future.
  14. 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.
  15. Zainal SFFS, Aziz HA, Omar FM, Alazaiza MYD
    Chemosphere, 2021 Dec;285:131484.
    PMID: 34261011 DOI: 10.1016/j.chemosphere.2021.131484
    Stabilised leachate usually contains lower concentration of organic compounds than younger leachate; it has low biodegradability and generally unsuitable for biological treatment. The effectiveness of tetravalent metal salts in a coagulation-flocculation (C-F) process is still inclusive. Application of natural coagulants as an alternative to the chemical could reduce chemical usage, is less costly, and environmentally friendly. Hence, the objective of the current research is to examine the possibility of reducing the amount of Tin (IV) chloride (SnCl4) as a primary coagulant by adding Jatropha curcas (JC) as a flocculant as a sole treatment through the C-F process in treating concentrated suspended solids (SS) (547 mg/L), colour (19,705 Pt-Co) and chemical oxygen demand (COD) (4202 mg/L) in stabilised landfill leachate. The work also aims to evaluate the sludge properties after treatment. Functional groups, such as carboxylic acids, hydroxyl and amine/amino compounds (protein contents), were detected in the JC seed to facilitate the C-F process by neutralising the charge pollutant in water and cause the possibility of hydrogen bonding interaction between molecules. The combination of JC seed (0.9 g/L) as a flocculant reduced the dosage of SnCl4 as a coagulant from 11.1 g/L to 8.5 g/L with removals of 99.78%, 98.53% and 74.29% for SS, colour and COD, respectively. The presence of JC improved the sludge property with good morphology; the particles were in a rectangular shape, had clumps and strong agglomeration. These properties of sludge proved that JC seed could enhance the adsorption and bridging mechanism in the C-F procedure.
  16. Arifin SNH, Radin Mohamed RMS, Al-Gheethi AA, Wei LC, Yashni G, Fitriani N, et al.
    Chemosphere, 2022 Jan;287(Pt 3):132278.
    PMID: 34826939 DOI: 10.1016/j.chemosphere.2021.132278
    The study explored the characteristics and effectiveness of modified TiO2 nanotubes with zeolite as a composite photocatalyst (MTNZC) for the degradation of triclocarban (TCC) from the aqueous solution. MTNZC samples have been produced via electrochemical anodisation (ECA) followed by electrophoretic deposition (EPD). Three independent factors selected include MTNZC size (0.5-1 cm2), pH (3-10), and irradiation time (10-60 min). The observation revealed that the surface of Ti substrate by the 40 V of anodisation and 3 h of calcination was covered with the array ordered, smooth and optimum elongated nanotubes with average tube length was approximately 5.1 μm. EDS analysis proved the presence of Si, Mg, Al, and Na on MTNZC due to the chemical composition present in the zeolite. The average crystallite size of TiO₂ nanotubes increased from 2.07 to 3.95 nm by increasing anodisation voltage (10, 40, and 60 V) followed by 450 °C of calcination for 1, 3, and 6 h, respectively. The optimisation by RSM shows the F-value (36.12), the p-value of all responses were less than 0.0001, and the 95% confidence level of the model by all the responses indicated the model was significant. The R2 in the range of 0.9433-0.9906 showed the suitability of the model to represent the actual relationship among the parameters. The photocatalytic degradation rate of TCC from the first and the fifth cycles were 94.2 and 77.4%, indicating the applicability of MTNZC to be used for several cycles.
  17. Jatoi AS, Mubarak NM, Hashmi Z, Solangi NH, Karri RR, Hua TY, et al.
    Chemosphere, 2023 Feb;313:137497.
    PMID: 36493892 DOI: 10.1016/j.chemosphere.2022.137497
    Multiple ecological contaminants in gaseous, liquid, and solid forms are vented into ecosystems due to the huge growth of industrialization, which is today at the forefront of worldwide attention. High-efficiency removal of these environmental pollutants is a must because of the potential harm to public health and biodiversity. The alarming concern has led to the synthesis of improved nanomaterials for removing pollutants. A path to innovative methods for identifying and preventing several obnoxious, hazardous contaminants from entering the environment is grabbing attention. Various applications in diverse industries are seen as a potential directions for researchers. MXene is a new, excellent, and advanced material that has received greater importance related to the environmental application. Due to its unique physicochemical and mechanical properties, high specific surface area, physiological compatibility, strong electrodynamics, and raised specific surface area wettability, its applications are growing. This review paper examines the most recent methods and trends for environmental pollutant removal using advanced 2D Mxene materials. In addition, the history and the development of MXene synthesis were elaborated. Furthermore, an extreme summary of various environmental pollutants removal has been discussed, and the future challenges along with their future perspectives have been illustrated.
  18. Abdullah RF, Rashid U, Hazmi B, Ibrahim ML, Tsubota T, Alharthi FA
    Chemosphere, 2022 Jan;286(Pt 3):131913.
    PMID: 34418662 DOI: 10.1016/j.chemosphere.2021.131913
    Hydrothermal carbonization (HTC) provides alternatives technique to produce a nanosize activated carbon from biomass with a high surface area. Herein, this study we prepared empty fruit bunch-based activated carbon (EFBHAC) using HTC technique. The activated carbon was then functionalized with K2CO3 and Cu(NO3)2 to produce bifunctional nano-catalyst for simultaneous esterification-transesterification of waste cooking oil (WCO). The physicochemical properties were performed i.e. N2 sorptions analysis, TPD-CO2/NH3, FESEM, EDX, FTIR and XRD analysis. The results revealed that produced EFBHAC possessed a BET surface area of 4056.17 m2 g-1, with pore volume of 0.827 cm3 g-1 and 5.42 nm of pore diameter resulting from hydrolysis, dehydration decarboxylation, aromatization and re-condensation during HTC process. Impregnation of EFBHAC with K2CO3 and Cu(NO3)2 granted a high amount of basicity and acidity of 9.21 mmol g-1 and 31.41 mmol g-1, respectively, accountable to high biodiesel yield of 97.1%, produced at the optimum condition of 5 wt% of catalyst loading, 12:1 of methanol to oil molar ratio at 70 °C for 2 h. More than 80% of biodiesel was produced after the 5th cycle depicted the good reusability. The transformations from WCO to biodiesel was confirmed via 1H NMR, FTIR and TGA analysis. Fuel properties revealed kinematic viscosity of 3.3 mm2 s-1, cetane number of 51, flash point of 160.5 °C, cloud and pour point of 11 °C and -3 °C, respectively. These results show the excellent potential of waste materials to prepare bifunctional nano-catalysts to produce higher biodiesel yield which has potential to be commercialized.
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