Displaying publications 81 - 100 of 402 in total

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  1. Dzinun H, Othman MHD, Ismail AF
    Chemosphere, 2019 Aug;228:241-248.
    PMID: 31035161 DOI: 10.1016/j.chemosphere.2019.04.118
    Comparison studies in suspension and hybrid photocatalytic membrane reactor (HPMR) system was investigated by using Reactive Black 5 (RB5) as target pollutant under UVA light irradiation. To achieve this aim, hybrid TiO2/clinoptilolite (TCP) photocatalyst powder was prepared by solid-state dispersion (SSD) methods and embedded at the outer layer of dual layer hollow fiber (DLHF) membranes fabricated via single step co-spinning process. TiO2 and CP photocatalyst were also used as control samples. The samples were characterized by Scanning Electron Microscopy (SEM), Energy Dispersion of X-ray (EDX), X-ray diffraction (XRD) and Brunauer-Emmett-Teller (BET) analyses. The result shows that TCP was actively functioned as photocatalyst in suspension system and 86% of RB5 photocatalytic degradation achieved within 60 min; however the additional step is required to separate the catalyst with treated water. In the HPMR system, even though the RB5 photocatalytic degradation exhibits lower efficiency however the rejection of RB5 was achieved up to 95% under UV irradiation due to the properties of photocatalytic membranes. The well dispersed of TCP at the outer layer of DLHF membrane have improved the surface affinity of DL-TCP membrane towards water, exhibit the highest pure water flux of 41.72 L/m2.h compared to DL-TiO2 membrane. In general, CP can help on improving photocatalytic activity of TiO2 in suspension, increased the RB5 removal and the permeability of DLHF membrane in HPMR system as well.
  2. Mpofu E, Alias A, Tomita K, Suzuki-Minakuchi C, Tomita K, Chakraborty J, et al.
    Chemosphere, 2021 Jun;273:129663.
    PMID: 33515965 DOI: 10.1016/j.chemosphere.2021.129663
    Azoxystrobin (AZ) is a broad-spectrum synthetic fungicide widely used in agriculture globally. However, there are concerns about its fate and effects in the environment. It is reportedly transformed into azoxystrobin acid as a major metabolite by environmental microorganisms. Bacillus licheniformis strain TAB7 is used as a compost deodorant in commercial compost and has been found to degrade some phenolic and agrochemicals compounds. In this article, we report its ability to degrade azoxystrobin by novel degradation pathway. Biotransformation analysis followed by identification by electrospray ionization-mass spectrometry (MS), high-resolution MS, and nuclear magnetic resonance spectroscopy identified methyl (E)-3-amino-2-(2-((6-(2-cyanophenoxy)pyrimidin-4-yl)oxy)phenyl)acrylate, or (E)-azoxystrobin amine in short, and (Z) isomers of AZ and azoxystrobin amine as the metabolites of (E)-AZ by TAB7. Bioassay testing using Magnaporthe oryzae showed that although 40 μg/mL of (E)-AZ inhibited 59.5 ± 3.5% of the electron transfer activity between mitochondrial Complexes I and III in M. oryzae, the same concentration of (E)-azoxystrobin amine inhibited only 36.7 ± 15.1% of the activity, and a concentration of 80 μg/mL was needed for an inhibition rate of 56.8 ± 7.4%, suggesting that (E)-azoxystrobin amine is less toxic than the parent compound. To our knowledge, this is the first study identifying azoxystrobin amine as a less-toxic metabolite from bacterial AZ degradation and reporting on the enzymatic isomerization of (E)-AZ to (Z)-AZ, to some extent, by TAB7. Although the fate of AZ in the soil microcosm supplemented with TAB7 will be needed, our findings broaden our knowledge of possible AZ biotransformation products.
  3. Sharif HMA, Mahmood N, Wang S, Hussain I, Hou YN, Yang LH, et al.
    Chemosphere, 2021 Jun;273:129695.
    PMID: 33524756 DOI: 10.1016/j.chemosphere.2021.129695
    Recently, the discharge of flue gas has become a global issue due to the rapid development in industrial and anthropogenic activities. Various dry and wet treatment approaches including conventional and hybrid hybrid wet scrubbing have been employing to combat against these toxic exhaust emissions. However, certain issues i.e., large energy consumption, generation of secondary pollutants, low regeneration of scrubbing liquid and high efficieny are hindering their practical applications on industrial level. Despite this, the hybrid wet scrubbing technique (advanced oxidation, ionic-liquids and solid engineered interface hybrid materials based techniques) is gaining great attention because of its low installation costs, simultaneous removal of multi-air pollutants and low energy requirements. However, the lack of understanding about the basic principles and fundamental requirements are great hurdles for its commercial scale application, which is aim of this review article. This review article highlights the recent developments, minimization of GHG, sustainable improvements for the regeneration of used catalyst via green and electron rich donors. It explains, various hybrid wet scrubbing techniques can perform well under mild condition with possible improvements such as development of stable, heterogeneous catalysts, fast and in-situ regeneration for large scale applications. Finally, it discussed recovery of resources i.e., N2O, NH3 and N2, the key challenges about several competitive side products and loss of catalytic activity over time to treat toxic gases via feasible solutions by hybrid wet scrubbing techniques.
  4. Yap JX, Leo CP, Mohd Yasin NH, Derek CJC
    Chemosphere, 2021 Jun;273:129657.
    PMID: 33524750 DOI: 10.1016/j.chemosphere.2021.129657
    Microalgae cultivation using open cultivation systems requires large area and it is susceptible to contamination as well as weather changes. Meanwhile, the closed systems require large capital investment, and they are susceptible to the build-up of dissolved oxygen. Air-liquid interface culture systems with low water-footprint, but high packing density can be used for microalgae cultivation if low-cost culture scaffolds are available. In this study, cellulose-based scaffolds were synthesized using NaOH/urea aqueous solution as the solvent. Titanium dioxide (TiO2), silica gel and polyethylene glycol 1000 (PEG 1000) nanoparticles were added into the membrane scaffolds to increase the hydrophilicity of nutrient absorbing to support the growth of microalgae. The membrane scaffolds were characterized by FTIR, SEM, contact angle, porosity and porometry. All three nanoparticles additives showed their ability in reducing the contact angle of membrane scaffolds from 63.4 ± 2.3° to a range of 52.6 ± 1.2° to 38.8 ± 1.5° due to the hydrophilic properties of the nanoparticles. The decreasing in pore size when nanoparticles were added did not affect the porosity of membrane scaffolds. Cellulose membrane scaffold with TiO2 showed the highest percentage of microalgae Navicula incerta growth rate of 22.1% because of the antibacterial properties of TiO2 in lowering the risk of cell contamination and enhancing the growth of N. incerta. The results exhibited that cellulose-based scaffold with TiO2 added could be an effective support in plant cell culture field.
  5. Mak TMW, Yu IKM, Xiong X, Zaman NQ, Yaacof N, Hsu SC, et al.
    Chemosphere, 2021 Jul;274:129750.
    PMID: 33549880 DOI: 10.1016/j.chemosphere.2021.129750
    To tackle the crisis associated with the rising commercial food waste generation, it is imperative to comprehend how corporates' recycling behaviour is influenced by different industry structures and economies. This study aims to fill in the information gap that various factors might be affecting corporates' recycling behaviour in two different economies due to environmental inequality by comparing upper-middle-income region (Malaysia) and high-income region (Hong Kong), respectively. A questionnaire survey regarding food waste management according to the Theory of Planned Behaviour was conducted with representatives coming from diverse industries of the hotel, food and beverage, and property management. The questionnaire responses were evaluated based on quantitative structural equation modelling and correlation analysis. The analysis results showed that the model fit the data well, explaining 78% of the variance in recycling behaviour. The findings demonstrated that the most substantial factor on individual's recycling intention by Malaysian commercial food waste generators was perceived behavioural control, and logistics and management incentives. Subjective norms demonstrated significant and adverse effects on the behaviour of food waste recycling. The variable of administrative incentives and corporate support presented strong positive correlations with moral attitudes as well as logistics and management incentives. Hotel industries from both Hong Kong and Malaysia have a higher acceptance level on human resources regarding food waste recycling. In comparison, food and beverage industries from both regions have a lower acceptance level. These findings could enrich our knowledge of the concerns in establishing regional policy strategies to encourage economic behavioural changes for sustainable development.
  6. Tan WK, Cheah SC, Parthasarathy S, Rajesh RP, Pang CH, Manickam S
    Chemosphere, 2021 Jul;274:129702.
    PMID: 33529956 DOI: 10.1016/j.chemosphere.2021.129702
    This investigation explores the efficacy of employing ultrasonic cavitation and coupling it with advanced oxidation processes (hydrogen peroxide and Fenton's reagent) for reducing the levels of total ammonia nitrogen in fish pond water containing Tilapia fishes. Ultrasonic cavitation is a phenomenon where the formation, growth and collapse of vaporous bubbles occur in a liquid medium producing highly reactive free radicals. Ultrasonic probe system (20 kHz with 750 W and 1000 W) was used to induce cavitation. Besides, to intensify the process, ultrasonic cavitation was coupled with hydrogen peroxide and Fenton's reagent. Using SERA colour indicator test kits, the levels of ammonium, nitrite and carbonate hardness were measured. The results obtained from this study clearly show that the advanced oxidation processes are more efficient in reducing the ammonium and nitrite levels in fish pond water than using ultrasound alone. The pH and carbonate hardness levels were not affected significantly by ultrasonic cavitation. The optimal treatment time and ultrasound power to treat the water samples were also established. Energy efficiency and cost analysis of this treatment have also been presented, indicating that ultrasonic cavitation coupled with hydrogen peroxide appears to be a promising technique for reducing total ammonia nitrogen levels in the fish pond water.
  7. Kadir AA, Abdullah SRS, Othman BA, Hasan HA, Othman AR, Imron MF, et al.
    Chemosphere, 2020 Nov;259:127468.
    PMID: 32603966 DOI: 10.1016/j.chemosphere.2020.127468
    In this study, two native duckweeds (Lemna minor and Azolla pinnata) were cultivated in Palm Oil Mill Effluent (POME) to extract nutrients from the effluent. Five grams of A. pinnata and 2 g of L. minor were transferred to 2 L POME (Initial concentrations: 198 mg/L COD, 4.3 mg/L nitrates, pH 9.53, 4 mg/L phosphate, 2.98 mg/L ammonia) with four different dilutions (2.5%, 5%, 10%, 15%) under greenhouse conditions. Samples of POME were taken every two days up to 10 days. Growth parameter, phosphate, ammonia, nitrates, pH, and COD were monitored within 10 days to select the most suitable growth medium for both plants. Results showed that 2.5% POME dilution had positive effect on L. minor growth and A. pinnata (wet weight increased by 8.7 g and 9.8 g, respectively), with all plants able to survive until the final day of exposure. The highest removal of ammonia was accomplished in 5% POME dilution by A. pinnata (98%) and L. minor (95.5%). The maximum phosphate removal was obtained in 10% POME dilution with 93.3% removal by A. pinnata and 86.7% by L. minor. Significant COD removal in 15% POME was obtained by L. minor (78%) and A. pinnata (66%). Both plants responded positively to the phytoremediation process, especially for A. pinnata which showed significant decreases in all parameters. The nutrient extraction by both plants from POME showed a positive effect on growth parameter, which has further promising potential to be used as animal feedstock.
  8. 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.
  9. Jaafar N, Musa SM, Azfaralariff A, Mohamed M, Yusoff AH, Lazim AM
    Chemosphere, 2020 Dec;260:127649.
    PMID: 32688323 DOI: 10.1016/j.chemosphere.2020.127649
    Post-digestion treatment is an important step during sample preparation to facilitate the removal of undigested materials for better detection of ingested microplastics. Sieving, density separation with zinc chloride solution (ZnCl2), and oil extraction protocol (OEP) have been introduced in separating microplastics from sediments. The clean-up methods are rarely highlighted in previous studies, especially in the separation of microplastics from marine biota. Thus, this study proposed and compared the suitability of three techniques, which can reduce the number of undigested particles from the digestate of GIT and gills. Our result has shown excellent removal of non-plastics materials and reduces the coloration of filter paper in all treated samples. Both sieving and density separation achieved optimum post-digestion efficiencies of >95% for both GIT and gill samples, which former showed no effect on polymer integrity. Additionally, high recovery rate was obtained for the larger size microplastics (>500 μm) with approximately 97.7% (GIT) and 95.7% (gill), respectively. Exposure to the ZnCl2 solution led to a significant loss of smaller size PET and changed the absorption spectrums of all tested polymers. Particle morphology determined by SEM revealed such exposure eroded the surface of PET fragments and elemental analysis has shown detectable peaks of zinc and chlorine appeared. Low microplastics recoveries were achieved through OPE and residue of oil was observed from the infrared spectrum of all tested polymer. The findings demonstrate sieving with size fractioning can provide exceptional removal of non-plastics materials from the digestate of GIT and gill samples.
  10. Cheng SY, Show PL, Juan JC, Chang JS, Lau BF, Lai SH, et al.
    Chemosphere, 2021 Jan;262:127829.
    PMID: 32768754 DOI: 10.1016/j.chemosphere.2020.127829
    Recent trend to recover value-added products from wastewater calls for more effective pre-treatment technology. Conventional landfill leachate treatment is often complex and thus causes negative environmental impacts and financial burden. In order to facilitate downstream processing of leachate wastewater for production of energy or value-added products, it is pertinent to maximize leachate treatment performance by using simple yet effective technology that removes pollutants with minimum chemical added into the wastewater that could potentially affect downstream processing. Hence, the optimization of coagulation-flocculation leachate treatment using multivariate approach is crucial. Central composite design was applied to optimize operating parameters viz. Alum dosage, pH and mixing speed. Quadratic model indicated that the optimum COD removal of 54% is achieved with low alum dosage, pH and mixing speed of 750 mgL-1, 8.5 and 100 rpm, respectively. Optimization result showed that natural pH of the mature landfill leachate sample is optimum for alum coagulation process. Hence, the cost of pH adjustment could be reduced for industrial application by adopting optimized parameters. The inherent mechanism of pollutant removal was elucidated by FTIR peaks at 3853 cm-1 which indicated that hydrogen bonds play a major role in leachate removal by forming well aggregated flocs. This is concordance with SEM image that the floc was well aggregated with the porous linkages and amorphous surface structure. The optimization of leachate treatment has been achieved by minimizing the usage of alum under optimized condition.
  11. Othman M, Latif MT, Jamhari AA, Abd Hamid HH, Uning R, Khan MF, et al.
    Chemosphere, 2021 Jan;262:127767.
    PMID: 32763576 DOI: 10.1016/j.chemosphere.2020.127767
    This study aimed to determine the spatial distribution of PM2.5 and PM10 collected in four regions (North, Central, South and East Coast) of Peninsular Malaysia during the southwest monsoon. Concurrent measurements of PM2.5 and PM10 were performed using a high volume sampler (HVS) for 24 h (August to September 2018) collecting a total of 104 samples. All samples were then analysed for water soluble inorganic ions (WSII) using ion chromatography, trace metals using inductively coupled plasma-mass spectroscopy (ICP-MS) and polycyclic aromatic hydrocarbon (PAHs) using gas chromatography-mass spectroscopy (GC-MS). The results showed that the highest average PM2.5 concentration during the sampling campaign was in the North region (33.2 ± 5.3 μg m-3) while for PM10 the highest was in the Central region (38.6 ± 7.70 μg m-3). WSII recorded contributions of 22% for PM2.5 and 20% for PM10 mass, with SO42- the most abundant species with average concentrations of 1.83 ± 0.42 μg m-3 (PM2.5) and 2.19 ± 0.27 μg m-3 (PM10). Using a Positive Matrix Factorization (PMF) model, soil fertilizer (23%) was identified as the major source of PM2.5 while industrial activity (25%) was identified as the major source of PM10. Overall, the studied metals had hazard quotients (HQ) value of <1 indicating a very low risk of non-carcinogenic elements while the highest excess lifetime cancer risk (ELCR) was recorded for Cr VI in the South region with values of 8.4E-06 (PM2.5) and 6.6E-05 (PM10). The incremental lifetime cancer risk (ILCR) calculated from the PAH concentrations was within the acceptable range for all regions.
  12. Ang TN, Young BR, Taylor M, Burrell R, Aroua MK, Chen WH, et al.
    Chemosphere, 2020 Dec;260:127496.
    PMID: 32659541 DOI: 10.1016/j.chemosphere.2020.127496
    Activated carbons have been reported to be useful for adsorptive removal of the volatile anaesthetic sevoflurane from a vapour stream. The surface functionalities on activated carbons could be modified through aqueous oxidation using oxidising solutions to enhance the sevoflurane adsorption. In this study, an attempt to oxidise the surface of a commercial activated carbon to improve its adsorption capacity for sevoflurane was conducted using 6 mol/L nitric acid, 2 mol/L ammonium persulfate, and 30 wt per cent (wt%) of hydrogen peroxide (H2O2). The adsorption tests at fixed conditions (bed depth: 10 cm, inlet concentration: 528 mg/L, and flow rate: 3 L/min) revealed that H2O2 oxidation gave desirable sevoflurane adsorption (0.510 ± 0.005 mg/m2). A parametric study was conducted with H2O2 to investigate the effect of oxidation conditions to the changes in surface oxygen functionalities by varying the concentration, oxidation duration, and temperature, and the Conductor-like Screening Model for Real Solvents (COSMO-RS) was applied to predict the interactions between oxygen functionalities and sevoflurane. The H2O2 oxidation incorporated varying degrees of both surface oxygen functionalities with hydrogen bond (HB) acceptor and HB donor characters under the studied conditions. Oxidised samples with enriched oxygen functionalities with HB acceptor character and fewer HB donor character exhibited better adsorption capacity for sevoflurane. The presence of a high amount of oxygen functional groups with HB donor character adversely affected the sevoflurane adsorption despite the enrichment of oxygen functional groups with HB acceptor character that have a higher tendency to adsorb sevoflurane.
  13. How SW, Nittami T, Ngoh GC, Curtis TP, Chua ASM
    Chemosphere, 2020 Nov;259:127444.
    PMID: 32640378 DOI: 10.1016/j.chemosphere.2020.127444
    In this study, we assessed and optimized a low-dissolved-oxygen oxic-anoxic (low-DO OA) process to achieve a low-cost and sustainable solution for wastewater treatment systems in the developing tropical countries treating low chemical oxygen demand-to-nitrogen ratio (COD/N) wastewater. The low-DO OA process attained complete ammonia removal and the effluent nitrate nitrogen (NO3-N) was below 0.3 mg/L. The recommended hydraulic retention time and sludge retention time (SRT) were 16 h and 20 days, respectively. The 16S rRNA sequencing data revealed that long SRT (20 days) encouraged the growth of nitrite-oxidizing bacteria (NOB) affiliated with "Candidatus Nitrospira defluvii". Comammox made up 10-20% of the Nitrospira community. NOB and comammox related to Nitrospira were enriched at long SRT (20 days) to achieve good low-DO nitrification performance. The low-DO OA process was efficient and has simpler design than conventional processes, which are keys for sustainable wastewater treatment systems in the developing countries treating low COD/N wastewater.
  14. Hussein M, Yoneda K, Mohd-Zaki Z, Amir A, Othman N
    Chemosphere, 2021 Mar;267:128874.
    PMID: 33199110 DOI: 10.1016/j.chemosphere.2020.128874
    Landfills are a potential threat to human health and the environment, especially from the detrimental and toxic heavy metals. This study focuses on the assessment of heavy metals contamination in leachate and surface soils from different landfills in Malaysia. Maximum quality rating scale (QRS) values of As (787) and Cr (552) denotes progressive deterioration of leachate contamination in landfill. The impacted soils showed high heavy metal concentrations especially at non-sanitary unlined landfills, as compared to background values, and natural soil nearby the landfills. In addition, to examine the environmental impacts of the landfill area (soil) in more detail, specific indexes; geo-accumulation index (Igeo), pollution index (PI) and integrated pollution index (IPI) were determined. Maximum As (3.122) and Cd (2.633) for Igeo and As (34.037) and Cd (20.881) for PI revealed that the soil samples in non-sanitary landfills were moderate to strongly polluted. The difference in range of IPI values for sanitary (0.294-0.322) and non-sanitary landfill soils (1.263-1.956) confirmed advanced decline of the soil quality in non-sanitary landfills. Arsenic concentrations were found to be statistically significant (ANOVA) for leachate and impacted soil in landfills investigated. It is also important to realize that rise in metal contents in landfill environments were not only caused by anthropogenic sources such as from the waste disposed, but also some other factors such as redox conditions, anoxic environments, pH, oxidation state of metals and microbial activities. Those conditions will actively promotes leaching of metals from waste and also natural soils in the landfill.
  15. Teh KC, Foo ML, Ooi CW, Leng Chew IM
    Chemosphere, 2021 Mar;267:129277.
    PMID: 33385850 DOI: 10.1016/j.chemosphere.2020.129277
    Cellulose nanocrystals (CNC) have received great research attention since the last few decades due to their extraordinary properties and wide range of applications. In this study, a sustainable and cost-effective method for the synthesis of lignin-containing cellulose nanocrystals (LCNC) from oil palm empty fruit bunch (EFB) is presented. This method is able to retain the lignin in EFB and manifest the properties of lignin. The proposed synthesis process is simpler than the conventional method of producing lignin-coated CNC by first removing the lignin to synthesize CNC followed by the re-coating of lignin on the structure. The samples of LCNC were characterized by transmission electron microscopy, X-ray diffraction, Fourier-transform infrared spectroscopy and water contact angle analysis. In addition, by altering the acid concentration during acid hydrolysis process (53% - 60% H2SO4), both surface hydrophobicity (66.0° - 75.1°) and length of LCNC (467 nm-177 nm) can be altered wherein a higher concentration of acid resulted in a greater contact angle and a shorter length of LCNC. Cost and energy analysis deduced that the proposed synthesis method saved about 62% of the total material cost and 80% less energy as compared to the synthesis of lignin-coated CNC.
  16. Van Tung T, Tran QB, Phuong Thao NT, Vi LQ, Hieu TT, Le S, et al.
    Chemosphere, 2020 Dec 15;268:129329.
    PMID: 33360937 DOI: 10.1016/j.chemosphere.2020.129329
    This study develops a method to reuse aquaculture wastewater and sediment from a catfish pond in order to increase agricultural productivity and protect the environment. Material flow analysis (MFA) is a central concept of this study that involves collecting catfish pond wastewater (CPW) and reusing it to irrigate five water spinach (Ipomoea aquatic) ponds before discharging it into a river. Typically, catfish pond sediment (CPS) was collected and composted to produce organic fertilizer for cornfields. The results revealed that pollutant removal efficiency of wastewater from CPW (by using water spinach) were total organic carbon (TOC) = 38.78%, nitrogen (N) = 27.07%, phosphorous (P) = 58.42%, and potassium (K) = 28.64%. By adding 20 tons of CPS compost per hectare of the cornfield, the corn yield boosted 15% compared to the control field. In addition, the water spinach grew and developed well in the medium of wastewater from the fish pond. Altogether, the results illustrate that catfish pond wastewater and sediment can act as organic fertilizers for crops meanwhile reduce environmental pollution from its reuse.
  17. Chew KW, Khoo KS, Foo HT, Chia SR, Walvekar R, Lim SS
    Chemosphere, 2020 Dec 15;268:129322.
    PMID: 33359993 DOI: 10.1016/j.chemosphere.2020.129322
    With the rapid urbanisation happening around the world followed by the massive demand for clean energy resources, green cities play a pivotal role in building a sustainable future for the people. The continuing depletion of natural resources has led to the development of renewable energy with algae as the promising source. The high growth rate of microalgae and their strong bio-fixation ability to convert CO2 into O2 have been gaining attention globally and intensive research has been conducted regarding the microalgae benefits. The focus on potential of microalgae in contributing to the development of green cities is rising. The advantage of microalgae is their ability to gather energy from sunlight and carbon dioxide, followed by transforming the nutrients into biomass and oxygen. This leads to the creation of green cities through algae cultivation as waste and renewable materials can be put to good use. The challenges that arise when using algae and the future prospect in terms of SDGs and economy will also be covered in this review. The future of green cities can be enhanced with the adaptation of algae as the source of renewable plants to create a better outlook of an algae green city.
  18. Almansoory AF, Idris M, Abdullah SRS, Anuar N, Kurniawan SB
    Chemosphere, 2021 Apr;269:128760.
    PMID: 33162166 DOI: 10.1016/j.chemosphere.2020.128760
    The greenhouse phytotoxicity experiment was conducted to analyse and assess the capability of Scirpus mucronatus (L.) in tolerating and removing petrol in contaminated soil. This research was conducted for 72 days by using 5, 10 and 30 g/kg petrol as soil contaminants. Results showed that the system planted with S. mucronatus (L.) had high potential to treat the 10 g/kg petrol-contaminated soil and had an average Total Petroleum Hydrocarbon (TPH) removal of 82.1%. At 5 and 30 g/kg petrol, the planted system removed 74.9% and 75.8% TPH, respectively. The petrol (10 g/kg) affected the plant growth positively, which was indicated by the increase in dry and wet weights throughout the research period. The removal of the TPH in the system was performed because of the interaction of plants and rhizobacteria. SEM showed that a high concentration of petrol (30 g/kg) affected the plant tissue negatively, as indicated by the altered structures of the root and stem cells. EDX results also confirmed that petrol was absorbed by the plant, as shown by the increased carbon content in the plant's root and stem after the treatment.
  19. 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.
  20. Kurniawan TA, Singh D, Avtar R, Othman MHD, Hwang GH, Albadarin AB, et al.
    Chemosphere, 2021 Jul;274:129986.
    PMID: 33979934 DOI: 10.1016/j.chemosphere.2021.129986
    This work investigates the performances of coconut shell waste-based activated carbon (CSWAC) adsorption in batch studies for removal of ammoniacal nitrogen (NH3-N) and refractory pollutants (as indicated by decreasing COD concentration) from landfill leachate. To valorize unused resources, coconut shell, recovered and recycled from agricultural waste, was converted into activated carbon, which can be used for leachate treatment. The ozonation of the CSWAC was conducted to enhance its removal performance for target pollutants. The adsorption mechanisms of refractory pollutants by the adsorbent are proposed. Perspectives on nutrient recovery technologies from landfill leachate from the view-points of downstream processing are presented. Their removal efficiencies for both recalcitrant compounds and ammoniacal nitrogen were compared to those of other techniques reported in previous work. It is found that the ozonated CSWAC substantially removed COD (i.e. 76%) as well as NH3-N (i.e. 75%), as compared to the CSWAC without pretreatment (i.e. COD: 44%; NH3-N: 51%) with NH3-N and COD concentrations of 2750 and 8500 mg/L, respectively. This reveals the need of ozonation for the adsorbent to improve its performance for the removal of COD and NH3-N at optimized reactions: 30 g/L of CSWAC, pH 8, 200 rpm of shaking speed and 20 min of reaction time. Nevertheless, treatment of the leachate samples using the ozonated CSWAC alone was still unable to result in treated effluents that could meet the COD and NH3-N discharge standards below 200 and 5 mg/L, respectively, set by legislative requirements. This reveals that another treatment is necessary to be undertaken to comply with the requirement of their effluent limit.
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