Displaying publications 241 - 260 of 3986 in total

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  1. Porous hexagonal nanoplate cobalt oxide derived from a coordination polymer as an effective catalyst for activating Oxone in water
    Tuan DD, Hung C, Da Oh W, Ghanbari F, Lin JY, Lin KA
    Chemosphere, 2020 Dec;261:127552.
    PMID: 32731015 DOI: 10.1016/j.chemosphere.2020.127552
    As cobalt (Co) represents an effective transition metal for activating Oxone to degrade contaminants, tricobalt tetraoxide (Co3O4) is extensively employed as a heterogeneous phase of Co for Oxone activation. Since Co3O4 can be manipulated to exhibit various shapes, 2-dimensional plate-like morphology of Co3O4 can offer large contact surfaces. If the large plate-like surfaces can be even porous, forming porous nanoplate Co3O4 (PNC), such a PNC should be a promising catalyst for Oxone activation. Therefore, a facile but straightforward method is proposed to prepare such a PNC for activating Oxone to degrade pollutants. In particular, a cobaltic coordination polymer with a morphology of hexagonal nanoplate, which is synthesized through coordination between Co2+ and thiocyanuric acid (TCA), is adopted as a precursor. Through calcination, CoTCA could be transformed into hexagonal nanoplate-like Co3O4 with pores to become PNC. This PNC also shows different characteristics from the commercial Co3O4 nanoparticle (NP) in terms of surficial reactivity and textural properties. Thus, PNC exhibits a much higher catalytic activity than the commercial Co3O4 NP towards activation of Oxone to degrade a model contaminant, salicylic acid (SA). Specifically, SA was 100% degraded by PNC activating Oxone within 120 min, and the Ea of SA degradation by PNC-activated Oxone is 70.2 kJ/mol. PNC can also remain stable and effective for SA degradation even in the presence of other anions, and PNC could be reused over multiple cycles without significant loss of catalytic activity. These features validate that PNC is a promising and useful Co-based catalyst for Oxone activation.
    Matched MeSH terms: Water; Water Pollutants, Chemical/analysis*; Water Purification/methods*
  2. Effects of land use configuration, seasonality and point source on water quality in a tropical watershed: A case study of the Johor River Basin
    Pak HY, Chuah CJ, Yong EL, Snyder SA
    Sci Total Environ, 2021 Aug 01;780:146661.
    PMID: 34030308 DOI: 10.1016/j.scitotenv.2021.146661
    Land use plays a significant role in determining the spatial patterns of water quality in the Johor River Basin (JRB), Malaysia. In the recent years, there have been several occurrences of pollution in these rivers, which has generated concerns over the long-term sustainability of the water resources in the JRB. Specifically, this water resource is a shared commodity between two states, namely, Johor state of Malaysia and Singapore, a neighbouring country adjacent to Malaysia. Prior to this study, few research on the influence of land use configuration on water quality have been conducted in Johor. In addition, it is also unclear how water quality varies under different seasonality in the presence of point sources. In this study, we investigated the influence of land use and point sources from wastewater treatment plants (WWTPs) on the water quality in the JRB. Two statistical techniques - Multivariate Linear Regression (MLR) and Redundancy Analysis (RA) were undertaken to analyse the relationships between river water quality and land use configuration, as well as point sources from WWTPs under different seasonality. Water samples were collected from 49 sites within the JRB from March to December in 2019. Results showed that influence from WWTPs on water quality was greater during the dry season and less significant during the wet season. In particular, point source was highly positively correlated with ammoniacal‑nitrogen (NH3-N). On the other hand, land use influence was greater than point source influence during the wet season. Residential and urban land use were important predictors for nutrients and organic matter (chemical oxygen demand); and forest land use were important sinks for heavy metals but a significant source of manganese.
    Matched MeSH terms: Fresh Water; Water Purification; Water Quality; Waste Water; Water Resources
  3. Bioremediation and Detoxification of the Textile Wastewater with Membrane Bioreactor Using the White-rot Fungus and Reuse of Wastewater
    Hossain K, Quaik S, Ismail N, Rafatullah M, Avasan M, Shaik R
    Iran J Biotechnol, 2016 Sep;14(3):154-162.
    PMID: 28959331 DOI: 10.15171/ijb.1216
    BACKGROUND: Application of membrane technology to wastewater treatment has expanded over the last decades due to increasingly stringent legislation, greater opportunities for water reuse/recycling processes and continuing advancement in membrane technology.

    OBJECTIVES: In the present study, a bench-scale submerged microfiltration membrane bioreactor (MBR) was used to assess the treatment of textile wastewater.

    MATERIALS AND METHODS: The decolorization capacity of white-rot fungus coriolus versicolor was confirmed through agar plate and liquid batch studies. The temperature and pH of the reactor were controlled at 29±1°C and 4.5±2, respectively. The bioreactor was operated with an average flux of 0.05 m.d(-1) (HRT=15hrs) for a month.

    RESULTS: Extensive growth of fungi and their attachment to the membrane led to its fouling and associated increase of the transmembrane pressure requiring a periodic withdrawal of sludge and membrane cleaning. However, stable decoloration activity (approx. 98%), BOD (40-50%), COD (50-67%) and total organic carbon (TOC) removal (>95%) was achieved using the entire system (fungi + membrane), while the contribution of the fungi culture alone for TOC removal, as indicated by the quality of the reactor supernatant, was 35-50% and 70%, respectively.

    CONCLUSIONS: The treated wastewater quality satisfied the requirement of water quality for dyeing and finishing process excluding light coloration. Therefore, textile wastewater reclamation and reuse is a promising alternative, which can both conserve or supplement the available water resource and reduce or eliminate the environmental pollution.

    Matched MeSH terms: Water; Water Purification; Water Quality; Waste Water; Water Resources
  4. Recent developments of zinc oxide based photocatalyst in water treatment technology: A review
    Lee KM, Lai CW, Ngai KS, Juan JC
    Water Res, 2016 Jan 01;88:428-448.
    PMID: 26519627 DOI: 10.1016/j.watres.2015.09.045
    Today, a major issue about water pollution is the residual dyes from different sources (e.g., textile industries, paper and pulp industries, dye and dye intermediates industries, pharmaceutical industries, tannery and craft bleaching industries, etc.), and a wide variety of persistent organic pollutants have been introduced into our natural water resources or wastewater treatment systems. In fact, it is highly toxic and hazardous to the living organism; thus, the removal of these organic contaminants prior to discharge into the environment is essential. Varieties of techniques have been employed to degrade those organic contaminants and advanced heterogeneous photocatalysis involving zinc oxide (ZnO) photocatalyst appears to be one of the most promising technology. In recent years, ZnO photocatalyst have attracted much attention due to their extraordinary characteristics. The high efficiency of ZnO photocatalyst in heterogeneous photocatalysis reaction requires a suitable architecture that minimizes electron loss during excitation state and maximizes photon absorption. In order to further improve the immigration of photo-induced charge carriers during excitation state, considerable effort has to be exerted to further improve the heterogeneous photocatalysis under UV/visible/solar illumination. Lately, interesting and unique features of metal doping or binary oxide photocatalyst system have gained much attention and became favourite research matter among various groups of scientists. It was noted that the properties of this metal doping or binary oxide photocatalyst system primarily depend on the nature of the preparation method and the role of optimum dopants content incorporated into the ZnO photocatalyst. Therefore, this paper presents a critical review of recent achievements in the modification of ZnO photocatalyst for organic contaminants degradation.
    Matched MeSH terms: Water Pollutants, Chemical/radiation effects*; Water Pollutants, Chemical/chemistry; Water Purification*
  5. Fulltext Magnetite nanoparticles in wastewater treatment
    Azdiya Suhada Abdul Rahim Arifin, Ismayadi Ismail, Abdul Halim Abdullah, Farah Nabilah Shafiee, Idza Riati Ibrahim
    The Pertanika Journal of Scholarly Research Reviews, 2016;2(3):108-122.
    MyJurnal
    Clean water is very important for health and well-being of humans and ecosystem. However, over the year, a billion tons of industrial waste, fertilizers and chemical waste were dumped untreated into water bodies, such as rivers, lake and oceans contributing towards water pollution, then threatening human health and ecosystem. Hence, the need for clean water has urged scientists to research and find solutions for improving water quality. Application of nanoparticles in wastewater treatment improves the environmental quality by elimination of harmful pollutants in wastewater. Magnetite is one of the nanoparticles used in wastewater treatment because of its specific large surface area, high reactivity in adsorption and recoverable from treated water via magnetic separation technology. Preparation method of magnetite nanoparticles is the important key to its adsorption efficiency.
    Matched MeSH terms: Water; Water Pollution; Water Purification; Water Quality; Waste Water
  6. Magnetic nanoparticles incorporation into different substrates for dyes and heavy metals removal-A Review
    Khan FSA, Mubarak NM, Tan YH, Karri RR, Khalid M, Walvekar R, et al.
    Environ Sci Pollut Res Int, 2020 Dec;27(35):43526-43541.
    PMID: 32909134 DOI: 10.1007/s11356-020-10482-z
    Substantial discharge of hazardous substances, especially dyes and heavy metal ions to the environment, has become a global concern due to many industries neglecting the environmental protocols in waste management. A massive discharge of contaminantsfrom different anthropogenic activities, can pose alarming threats to living species and adverse effect to the ecosystem stability. In the process of treating the polluted water, various methods and materials are used. Hybrid nanocomposites have attained numerous interest due to the combination of remarkable features of the organic and inorganic elements in a single material. In this regards, carbon and polymer based nanocomposites have gained particular interest because of their tremendous magnetic properties and stability. These nanocomposites can be fabricated using several approaches that include filling, template, hydrothermal, pulsed-laser irradiation, electro-spinning, detonation induced reaction, pyrolysis, ball milling, melt-blending, and many more. Moreover, carbon-based and polymer-based magnetic nanocomposites have been utilized for an extensive number of applications such as removal of heavy metal and dye adsorbents, magnetic resonance imaging, and drug delivery. This review emphasized mainly on the production of magnetic carbon and polymer nanocomposites employing various approaches and their applications in water and wastewater treatment. Furthermore, the future opportunities and challenges in applying magnetic nanocomposites for heavy metal ion and dye removal from water and wastewater treatment plant.
    Matched MeSH terms: Water Pollutants, Chemical*; Water Purification*; Waste Water
  7. Poly(amidoxime) ligand derived from waste palm fiber for the removal of heavy metals from electroplating wastewater
    Rahman ML, Fui CJ, Sarjadi MS, Arshad SE, Musta B, Abdullah MH, et al.
    Environ Sci Pollut Res Int, 2020 Sep;27(27):34541-34556.
    PMID: 32557073 DOI: 10.1007/s11356-020-09462-0
    A waste material known as palm oil empty fruit bunch (EFB) is used as a source of cellulose for the development of polymeric materials for the removal of metal ions from industrial wastewater. A poly(acrylonitrile)-grafted palm cellulose copolymer was synthesized by a conventional free radical initiating process followed by synthesis of a poly(amidoxime) ligand by oximation reaction. The resulting products were characterized by FT-IR, FE-SEM, EDX, TGA, DSC, and XPS. The poly(amidoxime) ligand was used to coordinate with and extract a series of transition metal ions from water samples. The binding capacity (qe) of the ligand with the metal ions such as copper, iron, cobalt, nickel, and lead were 260, 210, 168, 172, and 272 mg g-1, respectively at pH 6. The adsorption process followed the pseudo-first-order kinetic model (R2 > 0.99) and as well as the Freundlich isotherm model (R2 > 0.99) indicating the occurrence of a multi-layer adsorption process in the amidoxime ligand adsorbent. Results from reusability studies show that the ligand can be recycled for at least 10 cycles without any significant losses to its initial adsorption capacity. The synthesized polymeric ligand was shown to absorb heavy metals from electroplating wastewater with up to 95% efficiency.
    Matched MeSH terms: Water Pollutants, Chemical*; Water Purification*; Waste Water
  8. Fulltext Challenges and Opportunities of Biocoagulant/Bioflocculant Application for Drinking Water and Wastewater Treatment and Its Potential for Sludge Recovery
    Kurniawan SB, Abdullah SRS, Imron MF, Said NSM, Ismail N', Hasan HA, et al.
    Int J Environ Res Public Health, 2020 Dec 12;17(24).
    PMID: 33322826 DOI: 10.3390/ijerph17249312
    The utilization of metal-based conventional coagulants/flocculants to remove suspended solids from drinking water and wastewater is currently leading to new concerns. Alarming issues related to the prolonged effects on human health and further pollution to aquatic environments from the generated nonbiodegradable sludge are becoming trending topics. The utilization of biocoagulants/bioflocculants does not produce chemical residue in the effluent and creates nonharmful, biodegradable sludge. The conventional coagulation-flocculation processes in drinking water and wastewater treatment, including the health and environmental issues related to the utilization of metal-based coagulants/flocculants during the processes, are discussed in this paper. As a counterpoint, the development of biocoagulants/bioflocculants for drinking water and wastewater treatment is intensively reviewed. The characterization, origin, potential sources, and application of this green technology are critically reviewed. This review paper also provides a thorough discussion on the challenges and opportunities regarding the further utilization and application of biocoagulants/bioflocculants in water and wastewater treatment, including the importance of the selection of raw materials, the simplification of extraction processes, the application to different water and wastewater characteristics, the scaling up of this technology to a real industrial scale, and also the potential for sludge recovery by utilizing biocoagulants/bioflocculants in water/wastewater treatment.
    Matched MeSH terms: Water Purification*; Drinking Water*; Waste Water
  9. Fulltext Deriving freshwater quality criteria for iron, lead, nickel, and zinc for protection of aquatic life in Malaysia
    Shuhaimi-Othman M, Nadzifah Y, Nur-Amalina R, Umirah NS
    ScientificWorldJournal, 2012;2012:861576.
    PMID: 22919358 DOI: 10.1100/2012/861576
    Freshwater quality criteria for iron (Fe), lead (Pb), nickel (Ni), and zinc (Zn) were developed with particular reference to aquatic biota in Malaysia, and based on USEPA's guidelines. Acute toxicity tests were performed on eight different freshwater domestic species in Malaysia which were Macrobrachium lanchesteri (prawn), two fish: Poecilia reticulata and Rasbora sumatrana, Melanoides tuberculata (snail), Stenocypris major (ostracod), Chironomus javanus (midge larvae), Nais elinguis (annelid), and Duttaphrynus melanostictus (tadpole) to determine 96 h LC(50) values for Fe, Pb, Ni, and Zn. The final acute value (FAV) for Fe, Pb, Ni, and Zn were 74.5, 17.0, 165, and 304.9 μg L(-1), respectively. Using an estimated acute-to-chronic ratio (ACR) of 8.3, the value for final chronic value (FCV) was derived. Based on FAV and FCV, a criterion maximum concentration (CMC) and a criterion continuous concentration (CCC) for Fe, Pb, Ni, and Zn that are 37.2, 8.5, 82.5, and 152.4 μg L(-1) and 9.0, 2.0, 19.9, and 36.7 μg L(-1), respectively, were derived. The results of this study provide useful data for deriving national or local water quality criteria for Fe, Pb, Ni, and Zn based on aquatic biota in Malaysia. Based on LC(50) values, this study indicated that N. elinguis, M. lanchesteri, N. elinguis, and R. sumatrana were the most sensitive to Fe, Pb, Ni, and Zn, respectively.
    Matched MeSH terms: Fresh Water; Water Pollutants, Chemical/analysis*; Water Quality*
  10. Waste newspaper as cellulose resource of activated carbon by sodium salts for methylene blue and congo red removal
    Hao YS, Othman N, Zaini MAA
    Int J Biol Macromol, 2024 Oct;277(Pt 4):134353.
    PMID: 39089559 DOI: 10.1016/j.ijbiomac.2024.134353
    The work was aimed at evaluating the adsorptive properties of waste newspaper (WN) activated carbons chemically produced using sodium salts for methylene blue (MB) and congo red (CR) removal. The activated carbons, designated as AC1, AC2, AC3 and AC4 were prepared through impregnation with NaH2PO4, Na2CO3, NaCl and NaOH, respectively and activation at 500 °C for 1 h. The activated carbons were characterized for surface chemistry, thermal stability, specific area, morphology and composition. The AC1 with a surface area of 917 m2/g exhibits a greater MB capacity of 651 mg/g. Meanwhile, a greater CR capacity was recorded by AC2 at 299 mg/g. The pseudo-second order model fitted well with the kinetic data, while the equilibrium data could be described by Langmuir model. The thermodynamic parameters, i.e.., positive ΔH°, negative ΔG° and positive ΔS° suggest that the adsorption of dyes is endothermic, spontaneous and feasible at high solution temperature. To conclude, WN is a potential cellulose source for producing activated carbon, while NaH2PO4 activation could be employed to convert WN into activated carbon for effective dye wastewater treatment.
    Matched MeSH terms: Water Pollutants, Chemical/isolation & purification; Water Pollutants, Chemical/chemistry; Water Purification/methods
  11. Fulltext Polyelectrolytes ability in reducing atrazine concentration in water: surface effects
    Mohd Amin MF, Heijman SG, Lopes SI, Rietveld LC
    ScientificWorldJournal, 2014;2014:162157.
    PMID: 25197693 DOI: 10.1155/2014/162157
    This paper reports on the direct ability of two positively charged organic polyelectrolytes (natural-based and synthetic) to reduce the atrazine concentration in water. The adsorption study was set up using multiple glass vessels with different polymer dosing levels followed by ultrafiltration with a 1 kDa membrane. The addition of polymers exhibited a capability in reducing the atrazine concentration up to a maximum of 60% in surface-to-volume ratio experiments. In the beginning, the theoretical L-type of the isotherm of Giles' classification was expected with an increase in the dosage of the polymer. However, in this study, the conventional type of isotherm was not observed. It was found that the adsorption of the cationic polymer on the negatively charged glass surface was necessary and influential for the removal of atrazine. Surface-to-volume ratio adsorption experiments were performed to elucidate the mechanisms and the polymer configuration. The glass surface area was determined to be a limiting parameter in the adsorption mechanism.
    Matched MeSH terms: Water/chemistry*; Water Pollutants, Chemical/analysis*; Water Pollutants, Chemical/chemistry; Water Purification/methods*
  12. Optimization of circular plate separators with cross flow for removal of oil droplets and solid particles
    Ngu H, Wong KK, Law PL
    Water Environ Res, 2012 Apr;84(4):299-304.
    PMID: 22834217
    A circular gravity-phase separator using coalescing medium with cross flow was developed to remove oil and suspended solids from wastewaters. Coalescence medium in the form of inclined plates promotes rising of oil droplets through coalescence and settling of solid particles through coagulation. It exhibits 22.67% higher removal of total suspended solids (TSS) compared to separators without coalescing medium. Moreover, it removed more than 70% of oil compared to conventional American Petroleum Institute separators, which exhibit an average of 33% oil removal. The flowrate required to attain an effluent oil concentration of 10 mg/L (Q(o10)) at different influent oil concentrations (C(io)) can be represented by Q(o10) x 10(-5) = -0.0012C(io) + 0.352. The flowrate required to attain an effluent TSS concentration of 50 mg/L (Q(ss50)) at different influent TSS concentrations (C(iss)) can be represented by Q(ss50) x 10(-5) = 1.0 x 10(6) C(iss)(-2.9576). The smallest removable solid particle size was 4.87 microm.
    Matched MeSH terms: Water Movements; Water Pollutants, Chemical/isolation & purification*; Water Purification/instrumentation; Water Purification/methods*; Water Purification/standards
  13. Fulltext Bach adsorption study for the extraction of silver ions by hydrazone compounds from aqueous solution
    Mohamad Ali AS, Abdul Razak N, Ab Rahman I
    ScientificWorldJournal, 2012;2012:351967.
    PMID: 22629138 DOI: 10.1100/2012/351967
    Sorbent materials based on a hydrazone Schiff base compound, C(14)H(11)BrN(4)O(4), were prepared either by immobilizing the ligand into sol-gel (SG1) or bonding to silica (SG2). The sorbent materials were characterized by FT-IR, EDX, SEM, TEM, and TGA. The sorption characteristics of a matrix of eight transition metal ions (Ag(+), Cu(2+), Co(2+), Ni(2+), Fe(3+), Pb(2+), Zn(2+), and Mn(2+)) using batch method were studied. Several key parameters that affected the extraction efficiency such as pH, contact time, metal ions concentration, and gel size (for SGl) were investigated and optimized. Under the optimized conditions, the physically immobilized hydrazone sorbent (SG1) exhibits highest selectivity towards Ag(+) ions, while the chemically bonded hydrazone sorbent (SG2) exhibits high extraction for all metal ions tested. However, for practical applications such as the removal and preconcentration of Ag(+), the physically immobilized sorbent (SG1) is preferred.
    Matched MeSH terms: Water/chemistry*; Water Pollutants, Chemical/isolation & purification*; Water Pollutants, Chemical/chemistry; Water Purification/methods*
  14. Remediation technologies for heavy metal contaminated groundwater
    Hashim MA, Mukhopadhyay S, Sahu JN, Sengupta B
    J Environ Manage, 2011 Oct;92(10):2355-88.
    PMID: 21708421 DOI: 10.1016/j.jenvman.2011.06.009
    The contamination of groundwater by heavy metal, originating either from natural soil sources or from anthropogenic sources is a matter of utmost concern to the public health. Remediation of contaminated groundwater is of highest priority since billions of people all over the world use it for drinking purpose. In this paper, thirty five approaches for groundwater treatment have been reviewed and classified under three large categories viz chemical, biochemical/biological/biosorption and physico-chemical treatment processes. Comparison tables have been provided at the end of each process for a better understanding of each category. Selection of a suitable technology for contamination remediation at a particular site is one of the most challenging job due to extremely complex soil chemistry and aquifer characteristics and no thumb-rule can be suggested regarding this issue. In the past decade, iron based technologies, microbial remediation, biological sulphate reduction and various adsorbents played versatile and efficient remediation roles. Keeping the sustainability issues and environmental ethics in mind, the technologies encompassing natural chemistry, bioremediation and biosorption are recommended to be adopted in appropriate cases. In many places, two or more techniques can work synergistically for better results. Processes such as chelate extraction and chemical soil washings are advisable only for recovery of valuable metals in highly contaminated industrial sites depending on economical feasibility.
    Matched MeSH terms: Water Pollutants; Water Pollution*; Water Purification/methods*; Drinking Water*
  15. Time-lapse resistivity investigation of salinity changes at an ex-promontory land: a case study of Carey Island, Selangor, Malaysia
    Tajul Baharuddin MF, Taib S, Hashim R, Zainal Abidin MH, Ishak MF
    Environ Monit Assess, 2011 Sep;180(1-4):345-69.
    PMID: 21136290 DOI: 10.1007/s10661-010-1792-x
    Time-lapse resistivity measurements and groundwater geochemistry were used to study salinity effect on groundwater aquifer at the ex-promontory-land of Carey Island in Malaysia. Resistivity was measured by ABEM Terrameter SAS4000 and ES10-64 electrode selector. Relationship between earth resistivity and total dissolved solids (TDS) was derived, and with resistivity images, used to identify water types: fresh (ρ ( e ) > 6.5 Ω m), brackish (3 Ω m < ρ ( e ) < 6.5 Ω m), or saline (ρ ( e ) < 3 Ω m). Long-term monitoring of the studied area's groundwater quality via measurements of its time-lapse resistivity showed salinity changes in the island's groundwater aquifers not conforming to seawater-freshwater hydraulic gradient. In some aquifers far from the coast, saline water was dominant, while in some others, freshwater 30 m thick showed groundwater potential. Land transformation is believed to have changed the island's hydrogeology, which receives saltwater pressure all the time, limiting freshwater recharge to the groundwater system. The time-lapse resistivity measurements showed active salinity changes at resistivity-image bottom moving up the image for two seasons' (wet and dry) conditions. The salinity changes are believed to have been caused by incremental tide passing through highly porous material in the active-salinity-change area. The study's results were used to plan a strategy for sustainable groundwater exploration of the island.
    Matched MeSH terms: Fresh Water/chemistry*; Water Pollutants, Chemical/analysis*; Water Supply/statistics & numerical data; Water Cycle
  16. Removal of Ca2+ and Zn2+ from aqueous solutions by zeolites NaP and KP
    Yusof AM, Malek NA, Kamaruzaman NA, Adil M
    Environ Technol, 2010 Jan;31(1):41-6.
    PMID: 20232677 DOI: 10.1080/09593330903313794
    Zeolites P in sodium (NaP) and potassium (KP) forms were used as adsorbents for the removal of calcium (Ca2+) and zinc (Zn2+) cations from aqueous solutions. Zeolite KP was prepared by ion exchange of K+ with Na+ which neutralizes the negative charge of the zeolite P framework structure. The ion exchange capacity of K+ on zeolite NaP was determined through the Freundlich isotherm equilibrium study. Characterization of zeolite KP was determined using infrared spectroscopy and X-ray diffraction (XRD) techniques. From the characterization, the structure of zeolite KP was found to remain stable after the ion exchange process. Zeolites KP and NaP were used for the removal of Ca and Zn from solution. The amount of Ca2+ and Zn2+ in aqueous solution before and after the adsorption by zeolites was analysed using the flame atomic absorption spectroscopy method. The removal of Ca2+ and Zn2+ followed the Freundlich isotherm rather than the Langmuir isotherm model. This result also revealed that zeolite KP adsorbs Ca2+ and Zn2+ more than zeolite NaP and proved that modification of zeolite NaP with potassium leads to an increase in the adsorption efficiency of the zeolite. Therefore, the zeolites NaP and KP can be used for water softening (Ca removal) and reducing water pollution/toxicity (Zn removal).
    Matched MeSH terms: Water/chemistry*; Water Pollutants, Chemical/isolation & purification; Water Pollutants, Chemical/chemistry; Water Purification/methods*
  17. Cationic and anionic modifications of oil palm empty fruit bunch fibers for the removal of dyes from aqueous solutions
    Sajab MS, Chia CH, Zakaria S, Khiew PS
    Bioresour Technol, 2013 Jan;128:571-7.
    PMID: 23211482 DOI: 10.1016/j.biortech.2012.11.010
    Oil palm empty fruit bunch (EFB) fibers were employed to remove dyes from aqueous solutions via adsorption approaches. The EFB fibers were modified using citric acid (CA) and polyethylenimine (PEI) to produce anionic and cationic adsorbents, respectively. The CA modified EFB fibers (CA-EFB) and PEI-modified EFB fibers (PEI-EFB) were used to study the efficiency in removing cationic methylene blue (MB) and anionic phenol red (PR) from aqueous solutions, respectively, at different pHs, temperatures and initial dye concentrations. The adsorption data for MB on the CA-EFB fitted the Langmuir isotherm, while the adsorption of PR on the PEI-EFB fitted the Freundlich isotherm, suggesting a monolayer and heterogeneous adsorption behavior of the adsorption processes, respectively. Both modified fibers can be regenerated up to seven adsorption/desorption cycles while still providing as least 70% of the initial adsorption capacity.
    Matched MeSH terms: Water/chemistry*; Water Pollutants, Chemical/isolation & purification*; Water Pollutants, Chemical/chemistry; Water Purification/methods*
  18. Non-thermal plasma for air and water remediation
    Hashim SA, Samsudin FN, Wong CS, Abu Bakar K, Yap SL, Mohd Zin MF
    Arch Biochem Biophys, 2016 09 01;605:34-40.
    PMID: 27056469 DOI: 10.1016/j.abb.2016.03.032
    A modular typed dielectric barrier discharge (DBD) device is designed and tested for air and water remediation. The module is made of a number of DBD tubes that can be arranged in series or parallel. Each of the DBD tubes comprises inner electrode enclosed with dielectric barrier and arranged as such to provide a gap for the passage of gases. Non-thermal plasma generated in the gap effectively creates gaseous chemical reactions. Its efficacy in the remediation of gas stream containing high NOx, similar to diesel emission and wastewater containing latex, are presented. A six tubes DBD module has successfully removed more than 80% of nitric oxide from the gas stream. In another arrangement, oxygen was fed into a two tubes DBD to generate ozone for treatment of wastewater. Samples of wastewater were collected from a treatment pond of a rubber vulcanization pilot plant. The water pollution load was evaluated by the chemical oxygen demand (COD) and biological oxygen demand (BOD5) values. Preliminary results showed some improvement (about 13%) on the COD after treatment and at the same time had increased the BOD5 by 42%. This results in higher BOD5/COD ratio after ozonation which indicate better biodegradability of the wastewater.
    Matched MeSH terms: Water/chemistry*; Water Pollutants, Chemical/analysis*; Water Purification/methods*; Waste Water
  19. Public awareness level and occurrence of pharmaceutical residues in drinking water with potential health risk: A study from Kajang (Malaysia)
    Mohd Nasir FA, Praveena SM, Aris AZ
    Ecotoxicol Environ Saf, 2019 Dec 15;185:109681.
    PMID: 31561079 DOI: 10.1016/j.ecoenv.2019.109681
    Studies on the occurrence of pharmaceutical residues in drinking water were conducted especially in developed countries. However, limited studies reported the occurrence of pharmaceutical residues in developing countries. Thus, this study is conducted to fill the knowledge gap of pharmaceutical residue occurrences in developing countries, particularly in Malaysia, along with public awareness level and its potential human health risk. This study investigates public awareness level of drinking water quality and pharmaceutical handling, the occurrence of nine pharmaceutical residues (amoxicillin, caffeine, chloramphenicol, ciprofloxacin, dexamethasone, diclofenac, nitrofurazone, sulfamethoxazole, and triclosan) and potential human health risks in drinking water from Kajang (Malaysia) using commercially competitive enzyme-linked immunosorbent assay kits. In general, the public awareness level of Kajang population showed poor knowledge (82.02%), and less positive attitude (98.88%) with a good practice score (57.3%). Ciprofloxacin was detected at the highest concentration (0.667 ng/L) while amoxicillin was at the lowest concentration (0.001 ng/L) in drinking water from Kajang (Malaysia). Nevertheless, all the reported occurrences were lower than previous studies conducted elsewhere. There was no appreciable potential human health risk for all the pharmaceutical residues as the risk quotient (RQ) values were less than 1 (RQ water risk management and regulation in Malaysia.
    Matched MeSH terms: Water Pollutants, Chemical/analysis*; Water Quality*; Drinking Water/standards; Drinking Water/chemistry*
  20. Enhanced removal of Orange G from aqueous solutions by modified chitosan beads: Performance and mechanism
    Sutirman ZA, Sanagi MM, Abd Karim KJ, Abu Naim A, Wan Ibrahim WA
    Int J Biol Macromol, 2019 Jul 15;133:1260-1267.
    PMID: 31047925 DOI: 10.1016/j.ijbiomac.2019.04.188
    Grafting of crosslinked chitosan with monomer, N-vinyl-2-pyrrolidone, has been carried out to investigate its adsorption capacity toward Orange G (OG) from aqueous solutions. The adsorption performance of modified chitosan (cts(x)-g-PNVP) was examined and compared with that of the unmodified chitosan. The effects of initial pH, contact time and initial dye concentration were investigated in a batch system. The experimental data were correlated with the Langmuir and Freundlich isotherm models. The maximum adsorption capacity of cts(x)-g-PNVP (63.7mgg-1) based on Langmuir equation was relatively higher than that of the unmodified chitosan (1.7mgg-1). The kinetic studies showed that the adsorption process was consistent with the pseudo-second order kinetic model. Interaction mechanisms between OG and cts(x)-g-PNVP were also proposed. The overall results suggested that the prepared cts(x)-g-PNVP stands a good candidate as adsorbent for removal of anionic dye from aqueous solutions.
    Matched MeSH terms: Water/chemistry*; Water Pollutants, Chemical/isolation & purification; Water Pollutants, Chemical/chemistry; Water Purification/methods*
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