Displaying publications 1 - 20 of 48 in total

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  1. Fulltext A Review on Bacterial Contribution to Lignocellulose Breakdown into Useful Bio-Products
    Chukwuma OB, Rafatullah M, Tajarudin HA, Ismail N
    Int J Environ Res Public Health, 2021 Jun 03;18(11).
    PMID: 34204975 DOI: 10.3390/ijerph18116001
    Discovering novel bacterial strains might be the link to unlocking the value in lignocellulosic bio-refinery as we strive to find alternative and cleaner sources of energy. Bacteria display promise in lignocellulolytic breakdown because of their innate ability to adapt and grow under both optimum and extreme conditions. This versatility of bacterial strains is being harnessed, with qualities like adapting to various temperature, aero tolerance, and nutrient availability driving the use of bacteria in bio-refinery studies. Their flexible nature holds exciting promise in biotechnology, but despite recent pointers to a greener edge in the pretreatment of lignocellulose biomass and lignocellulose-driven bioconversion to value-added products, the cost of adoption and subsequent scaling up industrially still pose challenges to their adoption. However, recent studies have seen the use of co-culture, co-digestion, and bioengineering to overcome identified setbacks to using bacterial strains to breakdown lignocellulose into its major polymers and then to useful products ranging from ethanol, enzymes, biodiesel, bioflocculants, and many others. In this review, research on bacteria involved in lignocellulose breakdown is reviewed and summarized to provide background for further research. Future perspectives are explored as bacteria have a role to play in the adoption of greener energy alternatives using lignocellulosic biomass.
  2. Fulltext A Review on the Role of Earthworms in Plastics Degradation: Issues and Challenges
    Khaldoon S, Lalung J, Maheer U, Kamaruddin MA, Yhaya MF, Alsolami ES, et al.
    Polymers (Basel), 2022 Nov 07;14(21).
    PMID: 36365762 DOI: 10.3390/polym14214770
    Recently, the contribution of earthworms to plastic degradation and their capability to swallow smaller plastic fragments, known as microplastics, has been emphasized. The worm physically changes the size of microplastics and enhances microbial activities to increase the possibility of degradation. However, no research has shown that earthworms can chemically degrade microplastics to an element form, CO2 or H2O. In this review, previous research has been thoroughly explored to analyse the role that earthworms could play in plastic degradation in the soil. Earthworms can significantly affect the physical characteristics of plastics. However, earthworms' abilities to chemically degrade or change the chemical structure of plastics and microplastics have not been observed. Additionally, earthworms exhibit selective feeding behaviour, avoiding areas containing a high plastics concentration and rejecting plastics. Consequently, earthworms' abilities to adapt to the microplastics in soil in the environment can cause a problem. Based on this review, the challenges faced in earthworm application for plastic degradation are mostly expected to be associated with the toxicity and complexity of the plastic material and environmental factors, such as the moisture content of the soil and its temperature, microbial population, and feeding method.
  3. A novel agricultural waste adsorbent for the removal of lead (II) ions from aqueous solutions
    Ibrahim MN, Ngah WS, Norliyana MS, Daud WR, Rafatullah M, Sulaiman O, et al.
    J Hazard Mater, 2010 Oct 15;182(1-3):377-85.
    PMID: 20619537 DOI: 10.1016/j.jhazmat.2010.06.044
    The present study explores the ability of modified soda lignin (MSL) extracted from oil palm empty fruit bunches (EFB) in removing lead (II) ions from aqueous solutions. The effect of contact time, point zero charge (pH(pzc)) and pH of the solution, initial metal ion concentration and adsorbent dosage on the removal process were investigated. Furthermore, the MSL is characterized by SEM, XRF, FT-IR and surface area analysis. Equilibrium adsorption isotherms and kinetics were investigated. The experimental data were analyzed by the Langmuir, Freundlich and Temkin models of adsorption. The kinetic data obtained at different initial concentrations were analyzed using pseudo-first-order and pseudo-second-order models. The results provide strong evidence to support the hypothesis of adsorption mechanism.
  4. A review on chitosan-cellulose blends and nanocellulose reinforced chitosan biocomposites: Properties and their applications
    H P S AK, Saurabh CK, A S A, Nurul Fazita MR, Syakir MI, Davoudpour Y, et al.
    Carbohydr Polym, 2016 Oct 05;150:216-26.
    PMID: 27312632 DOI: 10.1016/j.carbpol.2016.05.028
    Chitin is one of the most abundant natural polymers in world and it is used for the production of chitosan by deacetylation. Chitosan is antibacterial in nature, non-toxic, and biodegradable thus it can be used for the production of biodegradable film which is a green alternative to commercially available synthetic counterparts. However, their poor mechanical and thermal properties restricted its wide spread applications. Chitosan is highly compatible with other biopolymers thus its blending with cellulose and/or incorporation of nanofiber isolated from cellulose namely cellulose nanofiber and cellulose nanowhiskers are generally useful. Cellulosic fibers in nano scale are attractive reinforcement in chitosan to produce environmental friendly composite films with improved physical properties. Thus chitosan based composites have wide applicability and potential in the field of biomedical, packaging and water treatment. This review summarises properties and preparation procedure of chitosan-cellulose blends and nano size cellulose reinforcement in chitosan bionanocomposites for different applications.
  5. Fulltext A review on the degradation of acetaminophen by advanced oxidation process: pathway, by-products, biotoxicity, and density functional theory calculation
    Qutob M, Hussein MA, Alamry KA, Rafatullah M
    RSC Adv, 2022 Jun 22;12(29):18373-18396.
    PMID: 35799916 DOI: 10.1039/d2ra02469a
    Water scarcity and the accumulation of recalcitrance compounds into the environment are the main reasons behind the attraction of researchers to use advanced oxidation processes (AOPs). Many AOP systems have been used to treat acetaminophen (ACT) from an aqueous medium, which leads to generating different kinetics, mechanisms, and by-products. In this work, state-of-the-art studies on ACT by-products and their biotoxicity, as well as proposed degradation pathways, have been collected, organized, and summarized. In addition, the Fukui function was used for predicting the most reactive sites in the ACT molecule. The most frequently detected by-products in this review were hydroquinone, 1,4-benzoquinone, 4-aminophenol, acetamide, oxalic acid, formic acid, acetic acid, 1,2,4-trihydroxy benzene, and maleic acid. Both the experimental and prediction tests revealed that N-(3,4-dihydroxy phenyl) acetamide was mutagenic. Meanwhile, N-(2,4-dihydroxy phenyl) acetamide and malonic acid were only found to be mutagenic in the prediction test. The findings of the LC50 (96 h) test revealed that benzaldehyde is the most toxic ACT by-products and hydroquinone, N-(3,4-dihydroxyphenyl)formamide, 4-methylbenzene-1,2-diol, benzoquinone, 4-aminophenol, benzoic acid, 1,2,4-trihydroxybenzene, 4-nitrophenol, and 4-aminobenzene-1,2-diol considered harmful. The release of them into the environment without treatment may threaten the ecosystem. The degradation pathway based on the computational method was matched with the majority of ACT proposed pathways and with the most frequent ACT by-products. This study may contribute to enhance the degradation of ACT by AOP systems.
  6. Abelmoschus esculentus (Okra) seed extract for stabilization of the biosynthesized TiO2 photocatalyst used for degradation of stable organic substance in water
    Aslam M, Abdullah AZ, Rafatullah M, Fawad A
    Environ Sci Pollut Res Int, 2022 Jan 27.
    PMID: 35083668 DOI: 10.1007/s11356-021-18066-1
    The seed extract of Abelmoschus esculentus (AE), also known as Okra, was used as a source of reducing and capping agents to synthesized biogenic titanium dioxide nanoparticles (TiO2 NPs) due to its rich flavonoid contents. The synthesized AE-TiO2 nanoparticles were further evaluated by the effect of loading of TiO2 NPs and irradiation time on the photocatalytic degradation of methylene blue dye. The synthesized TiO2 NPs were then characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), thermogravimetric analysis (TGA), energy dispersive X-ray spectroscopy (EDS), Fourier transformed infrared (FTIR) spectroscopy, Raman spectra, UV-visible spectrophotometry, and particle size distribution (PSD). The findings confirmed the successful synthesis of the spherical anatase phase of TiO2 NPs, as well as the existence of phytochemicals in the extract, which were involved in the capping/stabilization of NPs. The synthesized TiO2 NPs were found to be 60-120 nm in size and almost uniformly distributed throughout the sample. The photocatalytic activity measured in a 300 mL cylindrical photochemical reactor and irradiated with 250 watts UV lamp was investigated based on methylene blue degradation. Effects of irradiation time and catalyst loading were elucidated and correlated with the characteristics of the catalysts. The findings revealed that the synthesized TiO2 NPs were well-dispersed, stable, and could achieve more than 80 % degradation in 240 min of irradiation with 90 mg/L of AE-TiO2 NPs loading compared to only 70 % by the commercial one. These results suggested that AE-TiO2 NPs possesses significant catalytic activity, and the photocatalytic process could be used to degrade, decolorize, and mineralize the methylene blue dye. The polyphenolic tannins present in the extract were the reason behind the desirable characteristics of the nanoparticles and better photocatalytic activity of AE-TiO2 NPs.
  7. Fulltext Adsorption of Rhodamine B dye from aqueous solution onto acid treated banana peel: Response surface methodology, kinetics and isotherm studies
    Oyekanmi AA, Ahmad A, Hossain K, Rafatullah M
    PLoS One, 2019;14(5):e0216878.
    PMID: 31091269 DOI: 10.1371/journal.pone.0216878
    The adsorption of rhodamine B (RhB) using acid modified banana peels has been examined. Chemical characteristics of the adsorbents were observed in order to determine active functional groups. The major functional groups on the surface were OH, C = O, C = C and C-O-C. Interactions between operational parameters were studied using the central composite design (CCD) of response surface methodology (RSM). The predictions of the model output indicated that operational factors influenced responses at a confidence level of 95% (P<0.05). The optimum conditions for adsorption were pH 2 at a 0.2 g/L dose within 60 minutes of contact time. Isotherm studies were carried out using the optimized process variables. The data revealed that RhB adsorption fitted the Langmuir isotherm equation while the reduction of COD followed the Freundlich isotherm. Kinetic experiments fitted the pseudo second order model for RhB removal and COD reduction. The adsorption mechanism was not the only rate controlling step. Diffusion through the boundary layer described the pattern of adsorption.
  8. Adsorption of copper (II), chromium (III), nickel (II) and lead (II) ions from aqueous solutions by meranti sawdust
    Rafatullah M, Sulaiman O, Hashim R, Ahmad A
    J Hazard Mater, 2009 Oct 30;170(2-3):969-77.
    PMID: 19520510 DOI: 10.1016/j.jhazmat.2009.05.066
    The present study proposed the use of meranti sawdust in the removal of Cu(II), Cr(III), Ni(II) and Pb(II) ions from synthetic aqueous solutions. Batch adsorption studies showed that meranti sawdust was able to adsorb Cu(II), Cr(III), Ni(II) and Pb(II) ions from aqueous solutions in the concentration range 1-200mg/L. The adsorption was favoured with maximum adsorption at pH 6, whereas the adsorption starts at pH 1 for all metal ions. The effects of contact time, initial concentration of metal ions, adsorbent dosage and temperature have been reported. The applicability of Langmuir, Freundlich, and Dubinin-Radushkevich (D-R) isotherm was tried for the system to completely understand the adsorption isotherm processes. The adsorption kinetics tested with pseudo-first-order and pseudo-second-order models yielded high R(2) values from 0.850 to 0.932 and from 0.991 to 0.999, respectively. The meranti sawdust was found to be cost effective and has good efficiency to remove these toxic metal ions from aqueous solution.
  9. Adsorption of methylene blue on low-cost adsorbents: a review
    Rafatullah M, Sulaiman O, Hashim R, Ahmad A
    J Hazard Mater, 2010 May 15;177(1-3):70-80.
    PMID: 20044207 DOI: 10.1016/j.jhazmat.2009.12.047
    In this article, the use of low-cost adsorbents for the removal of methylene blue (MB) from solution has been reviewed. Adsorption techniques are widely used to remove certain classes of pollutants from waters, especially those which are not easily biodegradable. The removal of MB, as a pollutant, from waste waters of textile, paper, printing and other industries has been addressed by the researchers. Currently, a combination of biological treatment and adsorption on activated carbon is becoming more common for removal of dyes from wastewater. Although commercial activated carbon is a preferred adsorbent for color removal, its widespread use is restricted due to its relatively high cost which led to the researches on alternative non-conventional and low-cost adsorbents. The purpose of this review article is to organize the scattered available information on various aspects on a wide range of potentially low-cost adsorbents for MB removal. These include agricultural wastes, industrial solid wastes, biomass, clays minerals and zeolites. Agricultural waste materials being highly efficient, low cost and renewable source of biomass can be exploited for MB remediation. It is evident from a literature survey of about 185 recently published papers that low-cost adsorbents have demonstrated outstanding removal capabilities for MB.
  10. Advanced oxidation of polycyclic aromatic hydrocarbons in tropical soil: Self-catalytic utilization of natural iron contents in an oxygenation reactor supported with persulfate
    Qutob M, Rafatullah M, Muhammad SA, Siddiqui MR, Alam M
    Sci Total Environ, 2024 May 20;926:171843.
    PMID: 38521259 DOI: 10.1016/j.scitotenv.2024.171843
    The catalysts derived from natural iron minerals in the advanced oxidation process offer several advantages. However, their utilization in soil remediation is restricted due to the presence of soil impurities, which can inhibit the catalytic activity of these minerals. The soils in tropical regions exhibit lower organic matter content, limited cation exchange capacity, and are non-saline, this enhances the efficiency of utilizing natural iron minerals from tropical soil as a catalyst. In this regard, the catalytic potential of naturally iron-bearing tropical soil was investigated to eliminate phenanthrene (PHE), pyrene (PYR), and benzo[α]pyrene (B[α]P) using an oxygenated reactor supported with persulfate (PS). The system showed an efficient performance, and the removal efficiencies under the optimum conditions were 81 %, 73 %, and 86 % for PHE, PYR, and B[α]P, respectively. This indicated that the catalytic activity of iron was working efficiently. However, there were changes in the soil characteristics after the remediation process such as a significant reduction in iron and aluminum contents. The scavenging experiments demonstrated that HO• had a minor role in the oxidation process, SO4•- and O2•- emerged as the primary reactive species responsible for the effective degradation of the PAHs. Moreover, the by-products were monitored after soil remediation to evaluate their toxicity and to propose degradation pathways. The Mutagenicity test showed that two by-products from each PHE and B[α]P had positive results, while only one by-product of PYR showed positive. The toxicity tests of oral rat LD50 and developmental toxicity tests revealed that certain PAHs by-products could be more toxic from the parent pollutant itself. This study represents a notable progression in soil remediation by providing a step forward in the application of the advanced oxidation process (AOP) without requiring additional catalysts to activate oxidants and degrade pollutant PAHs from the soil.
  11. Fulltext Advancement in Benthic Microbial Fuel Cells toward Sustainable Bioremediation and Renewable Energy Production
    Umar MF, Rafatullah M, Abbas SZ, Mohamad Ibrahim MN, Ismail N
    Int J Environ Res Public Health, 2021 Apr 06;18(7).
    PMID: 33917378 DOI: 10.3390/ijerph18073811
    Anthropogenic activities are largely responsible for the vast amounts of pollutants such as polycyclic aromatic hydrocarbons, cyanides, phenols, metal derivatives, sulphides, and other chemicals in wastewater. The excess benzene, toluene and xylene (BTX) can cause severe toxicity to living organisms in wastewater. A novel approach to mitigate this problem is the benthic microbial fuel cell (BMFC) setup to produce renewable energy and bio-remediate wastewater aromatic hydrocarbons. Several mechanisms of electrogens have been utilized for the bioremediation of BTX through BMFCs. In the future, BMFCs may be significant for chemical and petrochemical industry wastewater treatment. The distinct factors are considered to evaluate the performance of BMFCs, such as pollutant removal efficiency, power density, and current density, which are discussed by using operating parameters such as, pH, temperature and internal resistance. To further upgrade the BMFC technology, this review summarizes prototype electrode materials, the bioremediation of BTX, and their applications.
  12. An insight into the role of experimental parameters in advanced oxidation process applied for pharmaceutical degradation
    Qutob M, Alshehri S, Shakeel F, Alam P, Rafatullah M
    Environ Sci Pollut Res Int, 2024 Apr;31(18):26452-26479.
    PMID: 38546921 DOI: 10.1007/s11356-024-33040-3
    The advanced oxidation process (AOP) is an efficient method to treat recalcitrance pollutants such as pharmaceutical compounds. The essential physicochemical factors in AOP experiments significantly influence the efficiency, speed, cost, and safety of byproducts of the treatment process. In this review, we collected recent articles that investigated the elimination of pharmaceutical compounds by various AOP systems in a water medium, and then we provide an overview of AOP systems, the formation mechanisms of active radicals or reactive oxygen species (ROS), and their detection methods. Then, we discussed the role of the main physicochemical parameters (pH, chemical interference, temperature, catalyst, pollutant concentration, and oxidant concentration) in a critical way. We gained insight into the most frequent scenarios for the proper and improper physicochemical parameters for the degradation of pharmaceutical compounds. Also, we mentioned the main factors that restrict the application of AOP systems in a commercial way. We demonstrated that a proper adjustment of AOP experimental parameters resulted in promoting the treatment performance, decreasing the treatment cost and the treatment operation time, increasing the safeness of the system products, and improving the reaction stoichiometric efficiency. The outcomes of this review will be beneficial for future AOP applicants to improve the pharmaceutical compound treatment by providing a deeper understanding of the role of the parameters. In addition, the proper application of physicochemical parameters in AOP systems acts to track the sustainable development goals (SDGs).
  13. Application of chitosan and its derivatives as adsorbents for dye removal from water and wastewater: a review
    Vakili M, Rafatullah M, Salamatinia B, Abdullah AZ, Ibrahim MH, Tan KB, et al.
    Carbohydr Polym, 2014 Nov 26;113:115-30.
    PMID: 25256466 DOI: 10.1016/j.carbpol.2014.07.007
    Chitosan based adsorbents have received a lot of attention for adsorption of dyes. Various modifications of this polysaccharide have been investigated to improve the adsorption properties as well as mechanical and physical characteristics of chitosan. This review paper discusses major research topics related to chitosan and its derivatives for application in the removal of dyes from water. Modification of chitosan changes the original properties of this material so that it can be more suitable for adsorption of different types of dye. Many chitosan derivatives have been obtained through chemical and physical modifications of raw chitosan that include cross-linking, grafting and impregnation of the chitosan backbone. Better understanding of these varieties and their affinity toward different types of dye can help future research to be properly oriented to address knowledge gaps in this area. This review provides better opportunity for researchers to better explore the potential of chitosan-derived adsorbents for removal of a great variety of dyes.
  14. Fulltext Bacterial Diversity and Community Structure of a Municipal Solid Waste Landfill: A Source of Lignocellulolytic Potential
    Chukwuma OB, Rafatullah M, Tajarudin HA, Ismail N
    Life (Basel), 2021 May 28;11(6).
    PMID: 34071172 DOI: 10.3390/life11060493
    Omics have given rise to research on sparsely studied microbial communities such as the landfill, lignocellulolytic microorganisms and enzymes. The bacterial diversity of Municipal Solid Waste sediments was determined using the illumina MiSeq system after DNA extraction and Polymerase chain reactions. Data analysis was used to determine the community's richness, diversity, and correlation with environmental factors. Physicochemical studies revealed sites with mesophilic and thermophilic temperature ranges and a mixture of acidic and alkaline pH values. Temperature and moisture content showed the highest correlation with the bacteria community. The bacterial analysis of the community DNA revealed 357,030 effective sequences and 1891 operational taxonomic units (OTUs) assigned. Forty phyla were found, with the dominant phyla Proteobacteria, Firmicutes, Actinobacteria, and Bacteroidota, while Aerococcus, Stenotrophomonas, and Sporosarcina were the dominant species. PICRUSt provided insight on community's metabolic function, which was narrowed down to search for lignocellulolytic enzymes' function. Cellulase, xylanase, esterase, and peroxidase were gene functions inferred from the data. This article reports on the first phylogenetic analysis of the Pulau Burung landfill bacterial community. These results will help to improve the understanding of organisms dominant in the landfill and the corresponding enzymes that contribute to lignocellulose breakdown.
  15. Fulltext Bio-Mediated Synthesis of Reduced Graphene Oxide Nanoparticles from Chenopodium album: Their Antimicrobial and Anticancer Activities
    Umar MF, Ahmad F, Saeed H, Usmani SA, Owais M, Rafatullah M
    Nanomaterials (Basel), 2020 Jun 01;10(6).
    PMID: 32492878 DOI: 10.3390/nano10061096
    A novel method of preparing reduced graphene oxide (RGOX) from graphene oxide (GOX) was developed employing vegetable extract, Chenopodium album, as a reducing and stabilizing agent. Chenopodium album is a green leafy vegetable with a low shelf life, fresh leaves of this vegetable are encouraged to be used due to high water content. The previously modified 'Hummers method' has been in practice for the preparation of GOX by using precursor graphite powder. In this study, green synthesis of RGOX was functionally verified by employing FTIR and UV-visible spectroscopy, along with SEM and TEM. Our results demonstrated typical morphology of RGOX stacked in layers that appeared as silky, transparent, and rippled. The antibacterial activity was shown by analyzing minimal inhibitory concentration values, agar diffusion assay, fluorescence techniques. It showed enhanced antibacterial activity against Gram-positive and Gram-negative bacteria in comparison to GOX. It has also been shown that the synthesized compound exhibited enhanced antibiofilm activity as compared to its parent compound. The efficacy of RGOX and GOX has been demonstrated on a human breast cancer cell line, which suggested RGOX as a potential anticancer agent.
  16. Bioelectricity production and xylene biodegradation through double chamber benthic microbial fuel cells fed with sugarcane waste as a substrate
    Umar MF, Rafatullah M, Abbas SZ, Ibrahim MNM, Ismail N
    J Hazard Mater, 2021 10 05;419:126469.
    PMID: 34192640 DOI: 10.1016/j.jhazmat.2021.126469
    Xylene, a recalcitrant compound present in wastewater from activities of petrochemical and chemical industries causes chronic problems for living organisms and the environment. Xylene contaminated wastewater may be biodegraded through a benthic microbial fuel cell (BMFC) as seen in this study. Xylene was oxidized into intermediate 3-methyl benzoic acid and entirely converted into non-toxic carbon dioxide. The highest voltage of the BMFC reactor was generated at 410 mV between 23 and 90 days when cell potential was 1 kΩ. The reactor achieved a maximum power density of about 63 mW/m2, and a current of 0.4 mA which was optimized from variable resistance (20 Ω - 1 kΩ). However, the maximum biodegradation efficiency of the BMFC was at 87.8%. The cyclic voltammetry curve helped to determine that the specific capacitance was 0.124 F/g after 30 days of the BMFC operation. Furthermore, the fitting equivalent circuit was observed with the help of Nyquist plot for calculating overall internal resistance of 65.82 Ω on 30th day and 124.5 Ω on 80th day. Staphylococcus edaphicus and Staphylococcus sparophiticus were identified by 16S rRNA sequencing as the dominant species in the control and BMFC electrode, presumably associated with xylene biodegradation.
  17. Fulltext Bioflocculants Produced by Bacterial Strains Isolated from Palm Oil Mill Effluent for Application in the Removal of Eriochrome Black T Dye from Water
    Abbas SZ, Yong YC, Ali Khan M, Siddiqui MR, Hakami AAH, Alshareef SA, et al.
    Polymers (Basel), 2020 Jul 13;12(7).
    PMID: 32668712 DOI: 10.3390/polym12071545
    Four strains of bioflocculant-producing bacteria were isolated from a palm oil mill effluent (POME). The four bacterial strains were identified as Pseudomonas alcaliphila (B1), Pseudomonas oleovorans (B2), Pseudomonas chengduensis (B3), and Bacillus nitratireducens (B4) by molecular identification. Among the four bacterial strains, Bacillus nitratireducens (B4) achieved the highest flocculating activity (49.15%) towards kaolin clay suspension after eight hours of cultivation time and was selected for further studies. The optimum conditions for Eriochrome Black T (EBT) flocculation regarding initial pH, type of cation, and B4 dosage were determined to be pH 2, Ca2⁺ cations, and a dosage of 250 mL/L of nutrient broth containing B4. Under these conditions, above 90% of EBT dye removal was attained. Fourier transform infrared spectroscopic (FT-IR) analysis of the bioflocculant revealed the presence of hydroxyl, alkyl, carboxyl, and amino groups. This bioflocculant was demonstrated to possess a good flocculating activity, being a promissory, low-cost, harmless, and environmentally friendly alternative for the treatment of effluents contaminated with dyes.
  18. 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.

  19. Fulltext Bioremediation and Electricity Generation by Using Open and Closed Sediment Microbial Fuel Cells
    Abbas SZ, Rafatullah M, Khan MA, Siddiqui MR
    Front Microbiol, 2018;9:3348.
    PMID: 30692985 DOI: 10.3389/fmicb.2018.03348
    The industrial contamination of marine sediments with mercury, silver, and zinc in Penang, Malaysia was studied with bio-remediation coupled with power generation using membrane less open (aerated) and closed (non-aerated) sediment microbial fuel cells (SMFCs). The prototype for this SMFC is very similar to a natural aquatic environment because it is not stimulated externally and an oxygen sparger is inserted in the cathode chamber to create the aerobic environment in the open SMFC and no oxygen supplied in the closed SMFC. The open and closed SMFCs were showed the maximum voltage generation 300.5 mV (77.75 mW/m2) and 202.7 mV (45.04 (mW/m2), respectively. The cyclic voltammetry showed the oxidation peak in open SMFCs at +1.9 μA and reduction peak at -0.3 μA but in closed SMFCs oxidation and reduction peaks were noted at +1.5 μA and -1.0 μA, respectively. The overall impedance (anode, cathode and solution) of closed SMFCs was higher than open SMFCs. The charge transfer impedance showed that the rates of substrate oxidation and reduction were very low in the closed SMFCs than open SMFCs. The Nyquist arc indicated that O2 act as electron acceptor in the open SMFCs and CO2 in the closed SMFCs. The highest remediation efficiency of toxic metals [Hg (II) ions, Zn (II) ions, and Ag (I) ions] in the open SMFCs were 95.03%, 86.69%, and 83.65% in closed SMFCs were 69.53%, 66.57%, and 65.33%, respectively, observed during 60-80 days. The scanning electron microscope and 16S rRNA analysis showed diverse exoelectrogenic community in the open SMFCs and closed SMFCs. The results demonstrated that open SMFCs could be employed for the power generation and bioremediation of pollutants.
  20. Fulltext Carbon Based Polymeric Nanocomposites for Dye Adsorption: Synthesis, Characterization, and Application
    Ali Khan M, Govindasamy R, Ahmad A, Siddiqui MR, Alshareef SA, Hakami AAH, et al.
    Polymers (Basel), 2021 Jan 28;13(3).
    PMID: 33525497 DOI: 10.3390/polym13030419
    Agglomeration and restacking can reduce graphene oxide (GO) activity in a wide range of applications. Herein, GO was synthesized by a modified Hummer's method. To minimize restacking and agglomeration, in situ chemical oxidation polymerization was carried out to embed polyaniline (PANI) chains at the edges of GO sheets, to obtain GO-PANI nanocomposite. The GO-PANI was tested for the adsorptive removal of brilliant green (BG) from an aqueous solution through batch mode studies. Infrared (FT-IR) analysis revealed the dominance of hydroxyl and carboxylic functionalities over the GO-PANI surface. Solution pH-dependent BG uptake was observed, with maximum adsorption at pH 7, and attaining equilibrium in 30 min. The adsorption of BG onto GO-PANI was fit to the Langmuir isotherm, and pseudo-second-order kinetic models, with a maximum monolayer adsorption capacity (qm) of 142.8 mg/g. An endothermic adsorption process was observed. Mechanistically, π-π stacking interaction and electrostatic interaction played a critical role during BG adsorption on GO-PANI.
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