Displaying publications 1 - 20 of 118 in total

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  1. Abdul Fattah Abu Bakar, Siti Nathasa Md Barkawi, Marlia Mohd. Hanafiah, Lee KE, Azhar Abdul Halim
    Sains Malaysiana, 2016;45:1509-1516.
    Keberkesanan rawatan air sisa industri automotif ditentukan dengan menggunakan kaedah penjerapan turus. Peratusan penyingkiran ammonia dan logam berat terpilih telah dikaji menggunakan pasir biasa dan pasir terubah suai secara kimia sebagai bahan penjerap. Dua model matematik iaitu Model Thomas serta Model Yoon-Nelson telah digunakan untuk menentukan kapasiti penjerapan maksimum ammonia. Peratusan penyingkiran ammonia menunjukkan pasir terubah suai secara kimia mencatatkan julat peratusan penyingkiran yang lebih tinggi iaitu 43.68% hingga 96.55% berbanding pasir biasa yang mencatatkan julat 0% hingga 89.66%. Logam berat zink, mangan, kromium, kuprum, arsenik, nikel, kobalt dan ferum mencatatkan peratusan penyingkiran antara 93% hingga 100% apabila menggunakan pasir terubah suai secara kimia manakala pasir biasa mencatatkan julat peratusan penyingkiran daripada 0.8% hingga 100%. Keputusan analisis menggunakan Model Thomas menunjukkan kapasiti penjerapan maksimum, qo ammonia menggunakan pasir terubah suai secara kimia (8.80 mg/g) adalah empat kali lebih tinggi daripada pasir biasa (2.57 mg/g) manakala masa bolos, t0.5 bahan penjerap yang ditentukan menggunakan Model Yoon dan Nelson mencatatkan masa tertinggi bagi pasir terubah suai secara kimia iaitu 30.18 min berbanding 9.57 min bagi pasir biasa. Kajian ini menunjukkan peratusan penyingkiran dan kapasiti penjerapan ammonia dan logam berat terpilih iaitu zink, mangan, kuprum, arsenik, nikel, kobalt dan ferum lebih tinggi bagi turus pasir terubah suai secara kimia berbanding pasir biasa.
    Matched MeSH terms: Ammonia
  2. Qamaruz-Zaman N, Abdul-Sukor NS, Ab-Rahman SA, Yaacof N
    Environ Sci Pollut Res Int, 2019 May;26(13):13658-13663.
    PMID: 30955198 DOI: 10.1007/s11356-019-04808-9
    Path analysis has been largely used in marketing research but has recently been applied in an environmental management context. This study evaluated the potential of path analysis in identifying the influence of moisture content on odor from decomposing food waste. Food waste with varying moisture content was monitored for odor concentration, microbial population density, oxygen uptake rate, volatile fatty acids, ammonia, and hydrogen sulfide. These various parameters were later analyzed using SmartPLS 3.0 software to produce the path analysis model using simultaneous equation modeling. Results indicate that odor concentration of food waste was not directly affected by moisture content (not significant, t-statistical 1.46  1.96) and subsequently odor. In order to manage food waste-related odors, it is recommended that the waste be kept at a moisture content lower than 40%. This is especially critical if prolonged storage is unavoidable.
    Matched MeSH terms: Ammonia/analysis*; Ammonia/chemistry
  3. Hossain KA, Mohd-Jaafar MN, Appalanidu KB, Mustafa A, Ani FN
    Environ Technol, 2005 Mar;26(3):251-9.
    PMID: 15881021
    Selective Non-Catalytic Reduction (SNCR) of nitric oxide has been studied experimentally by injecting aqueous urea solution with and without additive in a pilot-scale diesel fired tunnel furnace at 3.4% excess oxygen level and with low ppm of baseline NO(x) ranging from 65 to 75 ppm within the investigated temperature range. The tests have been carried out using commercial grade urea as NO(x) reducing agent and commercial grade sodium carbonate as additive. The furnace simulated the small-scale combustion systems, where the operating temperatures are usually in the range of about 973 to 1323 K and NO(x) emission level remains below 100 ppm. With 5% plain urea solution, at Normalized Stoichiometric Ratio (NSR) of 4 as much as 54% reduction was achieved at 1128 K, whilst in the additive case the NO(x) reduction was improved to as much as 69% at 1093 K. Apart from this improvement, in the additive case, the effective temperature window as well as peak temperature of NO(x) reduction shifted towards lower temperatures. The result is quite significant, especially for this investigated level of baseline NO(x). The ammonia slip measurements showed that in both cases the slip was below 16 ppm at NSR of 4 and optimum temperature of NO(x) reduction. Finally, the investigations demonstrated that urea based SNCR is quite applicable to small-scale combustion applications and commercial grade sodium carbonate is a potential additive.
    Matched MeSH terms: Ammonia/analysis*
  4. Dadrasnia A, Azirun MS, Ismail SB
    BMC Biotechnol., 2017 Nov 28;17(1):85.
    PMID: 29179747 DOI: 10.1186/s12896-017-0395-9
    BACKGROUND: When the unavoidable waste generation is considered as damaging to our environment, it becomes crucial to develop a sustainable technology to remediate the pollutant source towards an environmental protection and safety. The development of a bioengineering technology for highly efficient pollutant removal is this regard. Given the high ammonia nitrogen content and chemical oxygen demand of landfill leachate, Bacillus salmalaya strain 139SI, a novel resident strain microbe that can survive in high ammonia nitrogen concentrations, was investigated for the bioremoval of ammonia nitrogen from landfill leachate. The treatability of landfill leachate was evaluated under different treatment parameters, such as temperature, inoculum dosage, and pH.

    RESULTS: Results demonstrated that bioaugmentation with the novel strain can potentially improve the biodegradability of landfill leachate. B. salmalaya strain 139SI showed high potential to enhance biological treatment given its maximum NH3-N and COD removal efficiencies. The response surface plot pattern indicated that within 11 days and under optimum conditions (10% v/v inoculant, pH 6, and 35 °C), B. salmalaya strain139SI removed 78% of ammonia nitrogen. At the end of the study, biological and chemical oxygen demands remarkably decreased by 88% and 91.4%, respectively. Scanning electron microscopy images revealed that ammonia ions covered the cell surface of B. salmalaya strain139SI.

    CONCLUSIONS: Therefore, novel resistant Bacillus salmalaya strain139SI significantly reduces the chemical oxygen demand and NH3-N content of landfill leachate. Leachate treatment by B. salmalaya strain 139SI within 11 days.

    Matched MeSH terms: Ammonia/analysis*; Ammonia/metabolism; Ammonia/chemistry
  5. Arij Y, Fatihah S, Rakmi AR
    Bioresour. Technol., 2018 Jul;260:213-220.
    PMID: 29626780 DOI: 10.1016/j.biortech.2018.03.131
    The anaerobic treatment of leachate from a municipal waste transfer station in Malaysia was tested using a pilot scale anaerobic biofilm digester system that was operated under HRT sequence of 30-day, 25-day, 20-day and 10-day for 163 days under mesophilic conditions. Despite the leachate's complex characteristics, the system showed great performance given its maximum COD, BOD5 and total phosphorus removal efficiencies of 98 ± 1%, 99 ± 1% and 92 ± 9% respectively. The system was stable throughout its operation and showed optimal average values for the monitored parameters such as pH (7.53 ± 0.14), total VFA (79 ± 66 mg HOAc/L), alkalinity (10,919 ± 1556 mg CaCO3/L) and a non-toxic value for accumulated ammonia (960 ± 106 mg NH3-N/L). Measurement of the average daily biogas production yielded a value of 25 ± 1 m3/day throughout the system's operation with a composition of 57 ± 12% methane and 26 ± 6% carbon dioxide.
    Matched MeSH terms: Ammonia
  6. Saifful Kamaluddin Muzakir, Shahidan Radiman
    Sains Malaysiana, 2011;40:1123-1127.
    Nanozarah zink oksida telah disintesis menggunakan afrons gas koloid sebagai acuan. Zink sulfat (ZnSO4.7H2O) dan gas ammonia digunakan sebagi bahan tindak balas. Masa pengeraman yang dikaji adalah 2 jam dan 18 jam. Daripada analisis mikroskop elektron imbasan, morfologi nanohelaian dapat diperhatikan dengan ketebalan helaian 125 nm hingga 200 nm. Daripada analisis spektroskopi ultra lembayung-boleh nampak, saiz purata yang dianggarkan bagi sampel nanozarah zink oksida yang disintesis dengan masa pengeraman 2 jam adalah 2.03 nm dan 2.1 nm untuk sampel yang dieramkan selama 18 jam.
    Matched MeSH terms: Ammonia
  7. Suhaimi Suratman, Mohamad Awang, Loh AL, Norhayati Mohd Tahir
    Suatu kajian mengenai Indeks Kualiti Air (IKA) telah dijalankan di lembangan Sungai Paka, Terengganu. Ianya melibatkan pengukuran oksigen terlarut, pH, permintaan oksigen biokimia, permintaan oksigen kimia, jumlah pepejal terampai dan ammonia di lapan buah stesen pensampelan. Hasil kajian menunjukkan semua stesen pensampelan berada dalam status bersih kecuali dua stesen tercemar yang terletak di Sungai Rengat dan Sungai Rasau. Walau bagaimanapun, secara keseluruhannya purata nilai IKA bagi lembangan Sungai Paka adalah 72.4% dan boleh diklasifikasikan sebagai kelas II dengan status sedikit tercemar. Hasil kajian juga menunjukkan kumbahan daripada kilang kelapa sawit merupakan penyumbang utama kepada kemerosotan nilai IKA di kawasan kajian.
    Matched MeSH terms: Ammonia
  8. Mohd. Suhaimi Ahmad, Muhammad Ridwan Fahmi, Mustaqqim Abdul Rahim, Naimah Ibrahim
    Sains Malaysiana, 2016;45:1857-1867.
    Suatu kajian untuk menilai kesan gabungan aktiviti guna tanah dan perubahan musim terhadap kualiti sumber air telah dijalankan di Terusan Utara, Kedah. Kajian ini dijalankan di lima stesen terpilih selama 12 bulan berdasarkan Indeks Kualiti Air (WQI) dan Piawaian Interim Kualiti Air Kebangsaan (INWQS). Kajian mendapati kualiti air di Terusan Utara berada pada Kelas III dan berlaku peningkatan kualiti air dari hulu ke hilir. Hampir semua stesen berpotensi sebagai punca pencemaran berdasarkan aktiviti guna tanah terutamanya di Pelubang, Jitra serta Tunjang. Kajian menunjukkan terdapat perbezaan yang signifikan ketika perubahan musim pada DO, TSS serta BOD, namun tidak pada ammonia, pH dan COD. Secara amnya, kombinasi aktiviti guna tanah dan perubahan musim boleh mempengaruhi atau memberi kesan terhadap kualiti sumber air. Oleh itu, tindakan segera perlu dilakukan untuk mengawal punca pencemaran bagi memastikan kualiti sumber air di Terusan Utara kekal terpelihara.
    Matched MeSH terms: Ammonia
  9. Qamaruz-Zaman N, Milke MW
    Waste Manag, 2012 Dec;32(12):2426-30.
    PMID: 22819598 DOI: 10.1016/j.wasman.2012.06.023
    Research was conducted to determine suitable chemical parameters as indicators of odor from decomposing food wastes. Prepared food scraps were stored in 18 l plastic buckets (2 kg wet weight each) at 20 °C and 8 °C to reproduce high and low temperature conditions. After 1, 3, 7, 10 and 14 days of storage, the odor from the buckets were marked to an intensity scale of 0 (no odor) to 5 (intense) and the corresponding leachate analyzed for volatile fatty acids, ammonia and total organic carbon. A linear relationship between odor intensity and the measured parameter indicates a suitable odor indicator. Odor intensified with longer storage period and warmer surroundings. The study found ammonia and isovaleric acid to be promising odor indicators. For this food waste mixture, offensive odors were emitted if the ammonia and isovaleric acid contents exceeded 360 mg/l and 940 mg/l, respectively.
    Matched MeSH terms: Ammonia/chemistry*
  10. Hussain S, Aziz HA, Isa MH, Adlan MN, Asaari FA
    Bioresour. Technol., 2007 Mar;98(4):874-80.
    PMID: 16716587
    The purpose of the present study was to examine the removal of ammoniacal nitrogen (NH4-N) from synthetic wastewater using limestone (LS) and granular activated carbon (GAC) mixture as low cost adsorbent. In batch study, optimum shaking and settling times were 150 and 120 min, respectively. The LS-GAC mixture ratio of 25:15 removed about 58% NH4-N. The smaller particle size of medium yielded higher adsorption capacity. The equilibrium adsorption data followed the Freundlich isotherm (R2 > 0.98) but it showed weak bond. Adsorption kinetics were well described by the pseudo second-order rate model (R2 > 0.93). The upflow column showed that higher flow rate and initial concentration resulted in shorter column saturation time. The study showed that the usage of GAC could be reduced by combining GAC with LS for the removal of NH4-N from wastewater; thus reducing the cost of treatment.
    Matched MeSH terms: Ammonia/isolation & purification*
  11. Aziz HA, Adlan MN, Zahari MS, Alias S
    Waste Manag Res, 2004 Oct;22(5):371-5.
    PMID: 15560441
    The presence of ammoniacal nitrogen (N-NH3) in leachate is one of the problems normally faced by landfill operators. Slow leaching of wastes producing nitrogen and no significant mechanism for transformation of N-NH3 in the landfills causes a high concentration of ammoniacal nitrogen in leachate over a long period of time. A literature review showed that the removal of ammoniacal nitrogen from leachate was not well documented and to date, there were limited studies in Malaysia on this aspect, especially in adsorption treatment. The main objective of the present study was to investigate the suitability of activated carbon, limestone and a mixture of both materials as a filtering medium, in combination with other treatments capable of attenuating ammoniacal nitrogen which is present in significant quantity (between 429 and 1909 mg L(-1)) in one of the landfill sites in Malaysia. The results of the study show that about 40% of ammoniacal nitrogen with concentration of more than 1000 mg L(-1) could be removed either by activated carbon or a mixture of carbon with limestone at mixture ratio of 5:35. This result shows that limestone is potentially useful as a cost-effective medium to replace activated carbon for ammoniacal nitrogen removal at a considerably lower cost.
    Matched MeSH terms: Ammonia/chemistry*
  12. Bah AR, Rahman ZA
    ScientificWorldJournal, 2001 Nov 22;1 Suppl 2:90-5.
    PMID: 12805783
    Use of cheap, N-rich, and environmentally benign legume green manures to correct N deficiency in infertile soils is a very attractive option in the humid tropics. Understanding the influence of management and climate on their effectiveness, and quantifying their contribution to crop productivity, is therefore crucial for technology adoption and adaptation. Mineral N buildup and the contribution to N uptake in maize were studied in an Ultisol amended with fresh Gliricidia leaves. Net mineral N accumulation was compared in mulched and incorporated treatments in a field incubation study. The 15 N isotope dilution technique was used to quantify N supplied to maize by Gliricidia leaves in an alley cropping. Mineral N accumulation was slow, but was much greater after incorporation than after mulching. Also, N buildup was always higher in the topsoil (0 to 10 cm) than in the subsoil (10 to 20 cm). More NO3-N was leached than NH4-N, and the effect was greater in the incorporated treatment. Surface-applied Gliricidia leaves significantly increased N uptake by maize, and supplied >30% of the total N in the stover and >20% of that in the corn grain, even in the presence of hedgerows. Thus Gliricidia leaf mulch has immense potential to improve productivity in tropical soils.
    Matched MeSH terms: Ammonia/analysis
  13. Jung YH, Kim S, Yang TH, Lee HJ, Seung D, Park YC, et al.
    Bioprocess Biosyst Eng, 2012 Nov;35(9):1497-503.
    PMID: 22644062 DOI: 10.1007/s00449-012-0739-8
    Oil palm fronds are the most abundant lignocellulosic biomass in Malaysia. In this study, fronds were tested as the potential renewable biomass for ethanol production. The soaking in aqueous ammonia pretreatment was applied, and the fermentability of pretreated fronds was evaluated using simultaneous saccharification and fermentation. The optimal pretreatment conditions were 7 % (w/w) ammonia, 80 °C, 20 h of pretreatment, and 1:12 S/L ratio, where the enzymatic digestibility was 41.4 % with cellulase of 60 FPU/g-glucan. When increasing the cellulase loading in the hydrolysis of pretreated fronds, the enzymatic digestibility increased until the enzyme loading reached 60 FPU/g-glucan. With 3 % glucan loading in the SSF of pretreated fronds, the ethanol concentration and yield based on the theoretical maximum after 12 and 48 h of the SSF were 7.5 and 9.7 g/L and 43.8 and 56.8 %, respectively. The ethanol productivities found at 12 and 24 h from pretreated fronds were 0.62 and 0.36 g/L/h, respectively.
    Matched MeSH terms: Ammonia/chemistry*
  14. Akbari E, Buntat Z, Ahmad MH, Enzevaee A, Yousof R, Iqbal SM, et al.
    Sensors (Basel), 2014;14(3):5502-15.
    PMID: 24658617 DOI: 10.3390/s140305502
    Carbon Nanotubes (CNTs) are generally nano-scale tubes comprising a network of carbon atoms in a cylindrical setting that compared with silicon counterparts present outstanding characteristics such as high mechanical strength, high sensing capability and large surface-to-volume ratio. These characteristics, in addition to the fact that CNTs experience changes in their electrical conductance when exposed to different gases, make them appropriate candidates for use in sensing/measuring applications such as gas detection devices. In this research, a model for a Field Effect Transistor (FET)-based structure has been developed as a platform for a gas detection sensor in which the CNT conductance change resulting from the chemical reaction between NH3 and CNT has been employed to model the sensing mechanism with proposed sensing parameters. The research implements the same FET-based structure as in the work of Peng et al. on nanotube-based NH3 gas detection. With respect to this conductance change, the I-V characteristic of the CNT is investigated. Finally, a comparative study shows satisfactory agreement between the proposed model and the experimental data from the mentioned research.
    Matched MeSH terms: Ammonia/analysis
  15. Teh AA, Ahmad R, Kara M, Rusop M, Awang Z
    J Nanosci Nanotechnol, 2012 Oct;12(10):8201-4.
    PMID: 23421197
    We report the use of a new precursor as active agents to promote the growth of carbon nanotubes (CNT) in methane ambient using a simple thermal chemical vapour deposition method. The agents consist of ammonia and methanol mixed at different ratios and was found to enhance the growth of CNTs. The optimum methanol to ammonia ratio was found to be 8 to 5, whereby longer and denser CNTs were produced compared to other ratios. The result was found otherwise when the experiment was done solely in methane ambient. In addition, CNT growth on substrates coated with double layer Ni catalyst was improved in terms of quality and density compared to a single coated substrates. This finding is supported by Raman spectrometry analysis.
    Matched MeSH terms: Ammonia
  16. Ip YK, Leong MW, Sim MY, Goh GS, Wong WP, Chew SF
    J. Exp. Biol., 2005 May;208(Pt 10):1993-2004.
    PMID: 15879078
    The objective of this study was to elucidate if chronic and acute ammonia intoxication in mudskippers, Periophthalmodon schlosseri and Boleophthalmus boddaerti, were associated with high levels of ammonia and/or glutamine in their brains, and if acute ammonia intoxication could be prevented by the administration of methionine sulfoximine [MSO; an inhibitor of glutamine synthetase (GS)] or MK801 [an antagonist of N-methyl D-aspartate type glutamate (NMDA) receptors]. For P. schlosseri and B. boddaerti exposed to sublethal concentrations (100 and 8 mmol l(-1) NH4Cl, respectively, at pH 7.0) of environmental ammonia for 4 days, brain ammonia contents increased drastically during the first 24 h, and they reached 18 and 14.5 micromol g(-1), respectively, at hour 96. Simultaneously, there were increases in brain glutamine contents, but brain glutamate contents were unchanged. Because glutamine accumulated to exceptionally high levels in brains of P. schlosseri (29.8 micromol g(-1)) and B. boddaerti (12.1 micromol g(-1)) without causing death, it can be concluded that these two mudskippers could ameliorate those problems associated with glutamine synthesis and accumulation as observed in patients suffering from hyperammonemia. P. schlosseri and B. boddaerti could tolerate high doses of ammonium acetate (CH3COONH4) injected into their peritoneal cavities, with 24 h LC50 of 15.6 and 12.3 micromol g(-1) fish, respectively. After the injection with a sublethal dose of CH3COONH4 (8 micromol g(-1) fish), there were significant increases in ammonia (5.11 and 8.36 micromol g(-1), respectively) and glutamine (4.22 and 3.54 micromol g(-1), respectively) levels in their brains at hour 0.5, but these levels returned to normal at hour 24. By contrast, for P. schlosseri and B. boddaerti that succumbed within 15-50 min to a dose of CH3COONH4 (15 and 12 micromol g(-1) fish, respectively) close to the LC50 values, the ammonia contents in the brains reached much higher levels (12.8 and 14.9 micromol g(-1), respectively), while the glutamine level remained relatively low (3.93 and 2.67 micromol g(-1), respectively). Thus, glutamine synthesis and accumulation in the brain was not the major cause of death in these two mudskippers confronted with acute ammonia toxicity. Indeed, MSO, at a dosage (100 microg g(-1) fish) protective for rats, did not protect B. boddaerti against acute ammonia toxicity, although it was an inhibitor of GS activities from the brains of both mudskippers. In the case of P. schlosseri, MSO only prolonged the time to death but did not reduce the mortality rate (100%). In addition, MK801 (2 microg g(-1) fish) had no protective effect on P. schlosseri and B. boddaerti injected with a lethal dose of CH3COONH4, indicating that activation of NMDA receptors was not the major cause of death during acute ammonia intoxication. Thus, it can be concluded that there are major differences in mechanisms of chronic and acute ammonia toxicity between brains of these two mudskippers and mammalian brains.
    Matched MeSH terms: Ammonia/metabolism*; Glutamate-Ammonia Ligase/antagonists & inhibitors
  17. Siti A'iasah Hashim, Khairul Zaman Mohd Dahlan, Khomsaton Abu Bakar, Ayub Muhamad
    MyJurnal
    A laboratory scale test rig to treat simulated flue gas using electron beam technology was installed at the Alurtron EB-Irradiation Center, MINT. The experiment test rig was proposed as a result of feasibility studies conducted jointly by IAEA, MINT and TNB Research in 1997. The test rig system consists of several components, among others, diesel generator sets, pipe ducts, spray cooler, ammonia dosage system, irradiation vessel, bag filter and gas analyzers. The installation was completed and commissioned in October 2001. Results from the commissioning test runs and subsequent experimental work showed that the efficiency of flue gas treatment is high. It was proven that electron beam technology might be applied in the treatment of air pollutants. This paper describes the design and work function of the individual major components as well as the full system function. Results from the initial experimental works are also presented.
    Matched MeSH terms: Ammonia
  18. Nur Aqilah Muhamad Darif, Nur Shakila Abdul Samad, Sazlina Salleh, Mahadi Mohammad, Noor Alia Ahmad Nordin, Aysha Mariam Mohamed Javeed, et al.
    Trop Life Sci Res, 2016;27(11):71-77.
    MyJurnal
    Benthic faunal communities are important components in the intertidal zones.
    The diversity and abundance of the benthic communities are subjected to different natural
    and anthropogenic disturbances. The study was conducted as one off sampling on 6th
    November 2013 (1) to investigate the abundance and distribution of soft sediment
    communities in relation to environmental variables and (2) investigate the changes of
    population structure and diversity using spatial scales of 1 m, 10 m, and 100 m. Results
    indicated a total of 110 individuals of macrobenthos consisting of 7 different groups
    (Annelida, Bivalvia, Crustacea, Gastropoda, Nematoda, Nemertea, Polychaeta) and 4
    different groups of meiobenthos (Copepoda, Nematoda, Ostracoda, Polychaeta)
    consisting 920 individuals were recorded. Dissolved oxygen played the most significant
    role in affecting the distribution of soft sediment communities while ammonia
    concentrations only affected marcobenthic organisms. However, sediment grain size did
    not show significant correlation (p>0.05) on soft sediment communities. Hence,
    understanding how different properties of benthos respond to changes in environmental
    variables is crucial in determining how the impacts on the sediment are tolerated by the
    benthic organisms.
    Matched MeSH terms: Ammonia
  19. Koyama M, Nagao N, Syukri F, Rahim AA, Kamarudin MS, Toda T, et al.
    Bioresour. Technol., 2018 Oct;265:207-213.
    PMID: 29902653 DOI: 10.1016/j.biortech.2018.05.109
    Development of thermophilic composting for maximizing NH3 gas recovery would enable the production of a nitrogen source which is free from pathogen/heavy metal, for the cultivation of high-value microalgae. The present study examined the effect of NH3 recovery, nitrogen mass balance, and microbial community dynamics on thermophilic composting of shrimp aquaculture sludge. The emission of NH3 gas at 60 and 70 °C was 14.7% and 15.6%, respectively, which was higher than that at 50 °C (9.0%). The nitrogen mass balance analysis revealed that higher temperatures enhanced the solubilization of non-dissolved nitrogen and liberation of NH3 gas from the produced NH4+-N. High-throughput microbial community analysis revealed the shift of the dominant bacterial group from Bacillus to Geobacillus with the rise of composting temperature. In conclusion, thermophilic composting of shrimp aquaculture sludge at 60-70 °C was the most favorable condition for enhancing NH3 gas recovery.
    Matched MeSH terms: Ammonia
  20. Siti Nur Azella, Z., Noraini Muti, M.
    Malaysian Journal of Microscopy, 2015;11(1):115-120.
    MyJurnal
    Silicon dioxide (SiO2) has been extensively studied due to their unique properties that make it desirable for many applications ranging from electronic, catalysis, pigment as well as sensors. Multitude of methods and processes are established with the ability to manipulate and control the key properties that can cater for specific applications. Stober method is a very simple and easy for up-scale production of SiO2. This paper presents the experimental study on the effect of synthesis parameter on the morphology of SiO2 synthesized via Stober method. Three parameters were investigated such as concentration of catalyst, concentration of precursor and percentage of water content. The obtained samples were characterized using scanning electron microscopy (SEM) analysis. The findings showed that the size of particles produced is dependent on the synthesis parameter. In this study, particles size ranging from 50 nm to >100 nm are easily produced. The sphere size of SiO2 can be increased by increasing the concentration of ammonia hydroxide catalyst, the concentration of TEOS, as well as the percentage of water content.
    Matched MeSH terms: Ammonia
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