Displaying publications 41 - 60 of 1200 in total

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  1. Ogle CW, Ng YT
    Med J Malaya, 1969 Mar;23(3):174-8.
    PMID: 4240069
    Matched MeSH terms: Hydrogen-Ion Concentration
  2. Tee ZK, Jahim JM, Tan JP, Kim BH
    Bioresour Technol, 2017 Jun;233:296-304.
    PMID: 28285221 DOI: 10.1016/j.biortech.2017.02.110
    Calcium carbonate was evaluated as a replacement for the base during the fermentation of glycerol by a highly productive strain of 1,3-propanediol (PDO), viz., Clostridium butyricum JKT37. Due to its high specific growth rate (µmax=0.53h(-1)), 40g/L of glycerol was completely converted into 19.6g/L of PDO in merely 7h of batch fermentation, leaving only acetate and butyrate as the by-products. The accumulation of these volatile fatty acids was circumvented with the addition of calcium carbonate as the pH neutraliser before the fermentation was inoculated. An optimal amount of 15g/L of calcium carbonate was statistically determined from screening with various glycerol concentrations (20-120g/L). By substituting potassium hydroxide with calcium carbonate as the pH neutraliser for fermentation in a bioreactor, a similar yield (YPDO/glycerol=0.6mol/mol) with a constant pH was achieved at the end of the fermentation.
    Matched MeSH terms: Hydrogen-Ion Concentration
  3. Ng HS, Kee PE, Tan GY, Yim HS, Lan JC
    Appl Biochem Biotechnol, 2020 May;191(1):273-283.
    PMID: 32335865 DOI: 10.1007/s12010-020-03284-z
    Garcinia mangostana pericarp is a good source of natural antioxidants with numerous functional properties. The conventional approaches for the recovery of antioxidants from Garcinia mangostana pericarp require long processing time and high temperature, which may cause degradation or loss of bioactivity of antioxidants, and often result in low recovery efficiency. In this study, the extraction of antioxidants from Garcinia mangostana pericarp was investigated using a polyethylene glycol (PEG)/citrate aqueous biphasic system (ABS) with the addition of surfactants. The optimum condition for the recovery of antioxidants was achieved in PEG 1000/citrate ABS of pH 8 with tie-line length (TLL) of 48.3% (w/w), volume ratio (VR) of 1.6, 0.2% (w/w) sample loading and addition of 1.0% (w/w) Tween 85. The antioxidants were recovered in the PEG-rich top phase with a high K value of 18.23 ± 0.33 and a recovery yield of 92.01% ± 0.09. The findings suggested that the addition of surfactants to polymer/salt ABS can enhance the recovery of antioxidants from Garcinia mangostana pericarps by conserving the antioxidative properties.
    Matched MeSH terms: Hydrogen-Ion Concentration
  4. Ab Aziz MF, Hayat MN, Kaka U, Kamarulzaman NH, Sazili AQ
    Foods, 2020 Jun 04;9(6).
    PMID: 32512753 DOI: 10.3390/foods9060741
    Storage temperature and duration plays an important role in meat processing. Observations in poultry processing plants have shown a serious deviation in storage condition compared to the recommended procedures. Furthermore, there is still a paucity of evidence on the effects of storage temperature and duration on meat quality and microbial population. The aim of this study was to determine the effects of different temperature and duration during storage on physico-chemical properties and microbiological quality of broiler chicken Pectoralis major muscle. Eighty birds were slaughtered and processed, following which the packed boneless breast (PBB) (each bird was to provide two breast muscle samples; left breast and right breast) was divided into four groups, each consisted of 40 PBB. Each group was subsequently assigned to storage either at 4 °C, -10 °C, -18 °C or -40 °C, for 24 h before 20 PBB samples from each group were transported to the respective laboratory for meat quality and microbiological analysis. The remaining 20 PBB from each storage temperature were stored for 72 h before being transported for analysis. Results have shown significant increases in drip loss and cooking loss as the storage temperature decreases. Similarly, storage duration significantly affected cooking loss, of which, samples stored for 72 h exhibited higher cooking loss compared to those stored for 24 h. For color, significant differences were only observed in lightness (L*) and redness (a*) values. Longer duration of storage had significantly improved tenderness whereby, samples that have been stored for a shorter duration presented higher pH values. Populations of coliform and Salmonella decreased significantly with decreasing temperature and increasing storage duration.
    Matched MeSH terms: Hydrogen-Ion Concentration
  5. Naseem T, Bibi F, Arif S, Waseem M, Haq S, Azra MN, et al.
    Molecules, 2022 Oct 22;27(21).
    PMID: 36363976 DOI: 10.3390/molecules27217152
    In this work, graphene oxide (GO) and its reduced graphene oxide-zinc oxide nanocomposite (rGO-ZnO) was used for the removal of Cr (VI) from aqueous medium. By employing a variety of characterization techniques, morphological and structural properties of the adsorbents were determined. The adsorption study was done by varying concentration, temperature, pH, time, and amount of adsorbent. The results obtained confirmed that rGO-ZnO is a more economical and promising adsorbent for removing Cr (VI) as compared to GO. Kinetic study was also performed, which suggested that sorption of Cr (VI) follows the pseudo-first-order model. For equilibrium study, non-linear Langmuir was found a better fitted model than its linearized form. The maximum adsorption capacity calculated for GO and rGO-ZnO nanocomposite were 19.49 mg/g and 25.45 mg/g, respectively. Endothermic and spontaneous nature of adsorption was detected with positive values of ΔS (change in entropy), which reflects the structural changes happening at the liquid/solid interface.
    Matched MeSH terms: Hydrogen-Ion Concentration
  6. Hsu JL, Wang SS, Ooi CW, Thew XEC, Lai YR, Chiu CY, et al.
    Food Chem, 2023 Apr 16;406:135028.
    PMID: 36446280 DOI: 10.1016/j.foodchem.2022.135028
    The performance of lysozyme adsorption by the aminated nanofiber membrane immobilized with Reactive Green 19 (RG19) dyes was evaluated in batch and flow systems. The physicochemical properties of the dye-immobilized nanofiber membrane were characterized. The parameters of batch-mode adsorption of lysozyme (e.g., pH, initial dye concentration, and lysozyme concentration) were optimized using the Taguchi method. In a flow process, the factors influencing the dynamic binding performance for lysozyme adsorption in the chicken egg white (CEW) solution include immobilized dye concentration, adsorption pH value, feed flow rate, and feed CEW concentration. The impact of these operating conditions on the lysozyme purification process was investigated. Under optimal conditions, the recovery yield and purification factor of lysozyme achieved from the one-step adsorption process were 98.52% and 143 folds, respectively. The dye-affinity nanofiber membrane also did not exhibit any significant loss in its binding capacity and purification performance after five consecutive uses.
    Matched MeSH terms: Hydrogen-Ion Concentration
  7. Sarwar B, Khan AU, Aslam M, Bokhari A, Mubashir M, Alothman AA, et al.
    Environ Res, 2023 Mar 01;220:115168.
    PMID: 36584838 DOI: 10.1016/j.envres.2022.115168
    The inherent toxicity, mutagenicity and carcinogenicity of dyes that are discharged into aquatic ecosystems, harming the health of humans and animals. ZIF-8 based composites are regarded as good adsorbents for the breakdown of dyes in order to remove or degrade them. In the course of this research, metal-organic framework materials known as ZIF-8 and its two stable composites, ZIF-8/BiCoO3 (MZBC) and ZIF-8/BiYO3 (MZBY), were produced via a hydrothermal process and solvothermal process, respectively, for the dangerous Congo red (CR) dye removal from the solution in water using adsorption method. According to the findings, the most significant amount of CR dye that could be adsorbed is onto MZBC, followed by MZBY and ZIF-8. The pseudo-second-order kinetic model was used effectively to match the data for adsorption behavior and was confirmed using the Langmuir isotherm equation. There is a possibility that the pH and amount of adsorbent might influence the adsorption behavior of the adsorbents. According to the experiment results, the technique featured an endothermic adsorption reaction that spontaneously occurred. The higher adsorption capability of MZBC is because of the large surface area. This results in strong interactions between the functional groups on the surface of MZBC and CR dye molecules. In addition to the electrostatic connection between functional group Zn-O-H on the surface of ZIF-8 in MZBC and the -NH2 or SO3 functional group areas in CR molecules, it also includes the strong π-π interaction of biphenyl rings.
    Matched MeSH terms: Hydrogen-Ion Concentration
  8. Haq F, Kiran M, Chinnam S, Farid A, Khan RU, Ullah G, et al.
    Chemosphere, 2023 Apr;321:138000.
    PMID: 36724851 DOI: 10.1016/j.chemosphere.2023.138000
    In this research article, novel starch phosphate grafted polyvinyl imidazole (StP-g-PIMDZs) was synthesized. Firstly, a phosphate group was attached to starch polymer via a phosphorylation reaction. Next, 1-vinyl imidazole (VIMDZ) was grafted on the backbone of starch phosphate (StP) through a free radical polymerization reaction. The synthesis of these modified starches was confirmed by 1H NMR, 31P NMR and FT-IR techniques. The grafting of vinyl imidazole onto StP diminished the crystallinity. Due to the insertion of the aromatic imidazole ring, the StP-g-PIMDZs demonstrated greater thermal stability. The StP and StP-g-PIMDZs were used as sorbents for the adsorption of methylene blue dye (MBD) from the model solution. The maximum removal percentage for starch, StP, StP-g-PIMDZ 1, StP-g-PIMDZ 2 and StP-g-PIMDZ 3 was found to be 60.6%, 66.7%, 74.2%, 85.3 and 95.4%, respectively. The Pseudo second order kinetic model and Langmuir adsorption isotherm were best suited to the experimental data with R2 = 0.999 and 0.99, respectively. Additionally, the thermodynamic parameters showed that the adsorption process was feasible, spontaneous, endothermic and favored chemi-sorption mechanism.
    Matched MeSH terms: Hydrogen-Ion Concentration
  9. Hiew BYZ, Lee LY, Lee XJ, Thangalazhy-Gopakumar S, Gan S
    Environ Sci Pollut Res Int, 2021 Aug;28(30):40608-40622.
    PMID: 32601866 DOI: 10.1007/s11356-020-09594-3
    Heavy metals released by various industries are among the major pollutants found in water resources. In this research, biosorption technique was employed to remove cadmium (Cd2+) from an aqueous system using a novel biosorbent developed from okara waste (OW), a residue from soya bean-based food and beverage processing. Characterisation results revealed that the OW biosorbent contained functional groups such as hydroxyl-, carboxyl- and sulphur-based functional groups, and the surface of the biosorbent was rough with multiple fissures which might be the binding sites for the pollutant. The effects of dosage, solution pH, initial Cd2+ concentration, temperature and contact time were investigated using batch adsorption mode. The biosorption equilibrium and kinetic were best described by the Langmuir and Elovich models, respectively. The maximum biosorption capacities predicted by the Langmuir model were 10.91-14.80 mg/g at 30-70 °C, and the biosorption process was favourable as evident from 0 < RL < 1. The uptake of Cd2+ by the OW biosorbent was spontaneous and endothermic. The plausible biosorption mechanisms of this study could be ionic exchange, hydrogen bonding and electrostatic interactions. The Cd2+ loaded OW biosorbent could be regenerated using 0.4 M of HCl solution and regeneration was studied for 4 adsorption-desorption cycles. The present investigation supported that OW can be reused as a value-added biosorbent product for the removal of Cd2+ from the contaminated water.
    Matched MeSH terms: Hydrogen-Ion Concentration
  10. Tran TV, Jalil AA, Nguyen DTC, Nguyen TM, Alhassan M, Nabgan W, et al.
    Environ Res, 2023 May 15;225:115516.
    PMID: 36805897 DOI: 10.1016/j.envres.2023.115516
    Tetracycline (TCC) and sulfadiazine (SDZ) are two of the most consumed antibiotics for human therapies and bacterial infection treatments in aquafarming fields, but their accumulative residues can result in negative effects on water and aquatic microorganisms. Removal techniques are therefore required to purify water before use. Herein, we concentrate on adsorptive removal of TCC and SDZ using cobalt@carbon nanotubes (Co@CNTs) derived from Co-ZIF-67. The presence of CNTs on the edge of nanocomposites was observed. Taguchi orthogonal array was designed with four variables including initial concentration (5-20 mg L-1), dosage (0.05-0.2 g L-1), time (60-240 min), and pH (2-10). Concentration and pH were found to be main contributors to adsorption of tetracycline and sulfadiazine, respectively. The optimum condition was found at concentration 5 mg L-1, dosage 0.2 g L-1, contact time 240 min, and pH 7 for both TCC and SDZ removals. Confirmation tests showed that Co@CNTs-700 removed 99.6% of TCC and 97.3% of SDZ with small errors (3-5.5%). Moreover, the kinetic and isotherm were studied, which kinetic and isotherm data were best fitted with pseudo second-order model and Langmuir. Maximum adsorption capacity values for TCC and SDZ were determined at 118.4-174.1 mg g-1 for 180 min. We also proposed the main role of interactions such as hydrogen bonding, π-π stacking, and electrostatic attraction in the adsorption of antibiotics. With high adsorption performance, Co@CNTs-700 is expected to remove antibiotics efficiently from wastewater.
    Matched MeSH terms: Hydrogen-Ion Concentration
  11. Hussain NB, Akgül ET, Yılmaz M, Parlayıcı Ş, Hadibarata T
    Int J Phytoremediation, 2023;25(9):1199-1214.
    PMID: 36437736 DOI: 10.1080/15226514.2022.2144796
    The use of agricultural by-products such as Moringa oleifera plants is one effort to support the reduction of environmental pollution. Activated carbon produces from agricultural wastes is relatively less expensive and can replace traditional methods such as renewable as well as nonrenewable materials such as petroleum residue and coal. In this study, the removal of bisphenol A from aqueous media was studied using activated carbon produced from M. oleifera pods and peels. A batch adsorption study was carried out by varying the parameters of the adsorption process. A maximum removal percentage of 95.46% was achieved at optimum conditions of 2.5 g L-1 adsorbent dose, pH 7, 60 min contact time and 20 mg L-1 initial concentration of BPA. The BET surface areas of MOP, MOP-AC and MOP-ACZ were found to be 12.60, 4.10 and 45.96 m2/g, respectively. The experimental data were analyzed by Langmuir, Freundlich and Temkin adsorption isotherm models. Equilibrium data fitted well with the Langmuir isotherm with a maximum monolayer adsorption capacity of 20.14 mg g-1. The rates of adsorption were found to conform to the pseudo-second-order kinetics with a good correlation. The results indicate that the M. oleifera activated carbon could be employed as a low-cost alternative to commercial activated carbon in the removal of BPA from water.
    Matched MeSH terms: Hydrogen-Ion Concentration
  12. Kesavan S, Rajesh D, Shanmugam J, Aruna S, Gopal M, Vijayakumar S
    Int J Biol Macromol, 2023 Jul 31;244:125322.
    PMID: 37307980 DOI: 10.1016/j.ijbiomac.2023.125322
    A graphene oxide mediated hybrid nano system for pH stimuli-responsive and in vitro drug delivery targeted for cancer was described in this study. Graphene oxide (GO) functionalized Chitosan (CS) mediated nanocarrier capped with xyloglucan (XG) was fabricated with and without Kappa carrageenan (κ-C) from red seaweed, Kappaphycus alverzii, as an active drug. FTIR, EDAX, XPS, XRD, SEM and HR-TEM studies were carried out for GO-CS-XG nanocarrier loaded with and without active drugs to understand the physicochemical properties. XPS (C1s, N1s and O1s) confirmed the fabrications of XG and functionalization of GO by CS via the binding energies at 284.2 eV, 399.4 eV and 531.3 eV, respectively. The amount of drug loaded in vitro was 0.422 mg/mL. The GO-CS-XG nanocarrier showed a cumulative drug release of 77 % at acidic pH 5.3. In contrast to physiological conditions, the release rate of κ-C from the GO-CS-XG nanocarrier was considerably higher in the acidic condition. Thus, a pH stimuli-responsive anticancer drug release was successfully achieved with the GO-CS-XG-κ-C nanocarrier system for the first time. The drug release mechanism was carried out using various kinetic models that showed a mixed release behavior depending on concentration and diffusion/swelling mechanism. The best-fitting model which supports our release mechanism are zero order, first order and Higuchi models. GO-CS-XG and κ-C loaded nanocarrier biocompatibility were determined by in vitro hemolysis and membrane stabilization studies. MCF-7 and U937 cancer cell lines were used to study the cytotoxicity of the nanocarrier by MTT assay, which indicates excellent cytocompatibility. These findings support the versatile use of a green renewable biocompatible GO-CS-XG nanocarrier as targeted drug delivery and potential anticancer agent for therapeutic purposes.
    Matched MeSH terms: Hydrogen-Ion Concentration
  13. Ng ZJ, Abbasiliasi S, Yew Joon T, Ng HS, Phapugrangkul P, Tan JS
    Prep Biochem Biotechnol, 2023;53(7):872-879.
    PMID: 36594706 DOI: 10.1080/10826068.2022.2158468
    In this work, porous glass beads grafted with polyethylene glycol (PEG) were used as an adsorbent to purify lipase from Burkholderia metallica in column chromatography. The purification parameters viz. salt stability, types and concentrations of PEG and salt, pH of the binding solution, and flow rate were studied to determine the performance of the purification system in an XK16/20 column. The crude lipase was mixed with different types and concentrations of salts 1-5% (w/w) (sodium citrate, potassium citrate, and sodium acetate) and subjected to the column containing the polymeric glass bead. One-variable-at-a-time experimentation revealed that 20% (w/w) PEG 6000 g/mol impregnated glass beads with a binding solution of 5% sodium citrate at pH 7.7, a flow rate of 1.0 mL/min and extraction time of 10 min resulted in the highest purification factor and recovery yield at 3.67 and 88%, respectively. The purified lipase has 55 ∼ 60 kDa molecular mass. The outcome of the study showed PEG could be applied to modify the inert glass beads into polymeric form, providing a biocompatible and mild separation condition for lipase. Thus, PEG could be successfully applied for the purification of lipase from B. metallica fermentation broth using column chromatography.
    Matched MeSH terms: Hydrogen-Ion Concentration
  14. Mohamad NA, Nasef MM, Abdullah TAT, Ahmad A, Ting TM
    Environ Sci Pollut Res Int, 2023 Nov;30(55):116906-116920.
    PMID: 37121947 DOI: 10.1007/s11356-023-26913-6
    A series of fibrous aminated adsorbents for CO2 adsorption were prepared by covalent incorporation of poly (glycidyl methacrylate) (PGMA) by graft copolymerization of GMA onto electron beam (EB) irradiated polyethylenepolypropylene (PE/PP) fibrous sheets and subsequent amination with ethylenediamine (EDA), diethylenetriamine (DETA), or tetraethylenepentamine (TEPA). The physico-chemical properties of the adsorbents were evaluated using Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), thermogravimetric (TGA), X-ray diffraction (XRD), and Brunauer-Emmett-Teller (BET) analysis. All the adsorbents displayed typic primary and secondary amine features combined with a decrease in both of crystallinity and surface area of PE/PP, and such a decrease was higher in adsorbents with longer aliphatic chain of the amine. Of all adsorbents, TEPA-containing fibres showed the highest CO2 adsorption capacity and thus was further investigated for CO2 capture from CO2/CH4 mixtures of different gas ratios under various pressures and temperatures. The selectivity of CO2 over CH4 and equilibrium isotherms, kinetics, and thermodynamics of the adsorption on the fibrous aminated adsorbent were all investigated. The Sips model was found to best fit the isotherm of CO2 adsorption suggesting the presence of a combination of monolayer and multilayer adsorptions. The adsorption kinetic data was found to best fit Elovich model reflecting chemisorption. The ΔG°, ΔS°, and ΔH° showed positive values suggesting that the adsorption of CO2 on the present fibrous adsorbent was non-spontaneous with an increase in randomness implying that the process was endothermic. Overall, it can be suggested that PE/PP-g-PGMA/TEPA adsorbent has a strong potential for separation of CO2 from NG.
    Matched MeSH terms: Hydrogen-Ion Concentration
  15. Agha HM, Abdulhameed AS, Jawad AH, Aazmi S, Sidik NJ, De Luna Y, et al.
    Int J Biol Macromol, 2024 Feb;258(Pt 1):128792.
    PMID: 38110162 DOI: 10.1016/j.ijbiomac.2023.128792
    Herein, a natural material including chitosan (CTS) and algae (food-grade algae, FGA) was exploited to attain a bio-adsorbent (CTS/FGA) for enhanced methyl violet 2B dye removal. A study of the FGA loading into CTS matrix showed that the best mixing ratio between CTS and FGA to be used for the MV 2B removal was 50 %:50 % (CTS/FGA; 50:50 w/w). The present study employed the Box-Behnken design (RSM-BBD) to investigate the impact of three processing factors, namely CTS/FGA-(50:50) dose (0.02-0.1 g/100 mL), pH of solution (4-10), and contact time (5-15 min) on the decolorization rate of MV 2B dye. The results obtained from the equilibrium and kinetic experiments indicate that the adsorption of MV 2B dye on CTS/FGA-(50:50) follows the Langmuir and pseudo-second-order models, respectively. The CTS/FGA exhibits an adsorption capacity of 179.8 mg/g. The characterization of CTS/FGA-(50:50) involves the proposed mechanism of MV 2B adsorption, which primarily encompasses various interactions such as electrostatic forces, n-π stacking, and H-bonding. The present study demonstrates that CTS/FGA-(50:50) synthesized material exhibits a distinctive structure and excellent adsorption properties, thereby providing a viable option for the elimination of toxic cationic dyes from polluted water.
    Matched MeSH terms: Hydrogen-Ion Concentration
  16. Amari A, Elboughdiri N, Ahmed Said E, Zahmatkesh S, Ni BJ
    J Environ Manage, 2024 Feb;351:119761.
    PMID: 38113785 DOI: 10.1016/j.jenvman.2023.119761
    The practice of aquaculture is associated with the generation of a substantial quantity of effluent. Microalgae must effectively assimilate nitrogen and phosphorus from their surrounding environment for growth. This study modeled the algal biomass film, NO3-N concentration, and pH in the membrane bioreactor using the response surface methodology (RSM) and an artificial neural network (ANN). Furthermore, it was suggested that the optimal condition for each parameter be determined. The results of ANN modeling showed that ANN with a structure of 5-3 and employing the transfer functions tansig-logsig demonstrated the highest level of accuracy. This was evidenced by the obtained values of coefficient (R2) = 0.998, R = 0.999, mean squared error (MAE) = 0.0856, and mean square error (MSE) = 0.143. The ANN model, characterized by a 5-5 structure and employing the tansig-logsig transfer function, demonstrates superior accuracy when predicting the concentration of NO3-N and pH. This is evidenced by the high values of R2 (0.996), R (0.998), MAE (0.00162), and MSE (0.0262). The RSM was afterward employed to maximize the performance of algal film biomass, pH levels, and NO3-N concentrations. The optimal conditions for the algal biomass film were a concentration of 2.884 mg/L and a duration of 6.589 days. Similarly, the most favorable conditions for the NO3-N concentration and pH were 2.984 mg/L and 6.787 days, respectively. Therefore, this research uses non-dominated sorting genetic algorithm II (NSGA II) to find the optimal NO3-N concentration, algal biomass film, and pH for product or process quality. The region has the greatest alkaline pH and lowest NO3-N content.
    Matched MeSH terms: Hydrogen-Ion Concentration
  17. Hussain A, Maitra J, Saifi A, Ahmed S, Ahmed J, Shrestha NK, et al.
    Environ Res, 2024 Mar 01;244:117952.
    PMID: 38113992 DOI: 10.1016/j.envres.2023.117952
    In developing countries like India, an economically viable and ecologically approachable strategy is required to safeguard the drinking water. Excessive fluoride intake through drinking water can lead to dental fluorosis, skeletal fluorosis, or both. The present study has been under with an objective to investigate the feasibility of using cellulose derived from coconut fiber as an adsorbent under varying pH conditions for fluoride elimination from water. The assessment of equilibrium concentration of metal ions using adsorption isotherms is an integral part of the study. This present finding indicates the considerable effect of variation of adsorbent dosages on the fluoride removal efficiency under constant temperature conditions of 25 ± 2 °C with a contact period of 24 h. It is pertinent to mention that maximum adsorption of 88% has been observed with a pH value of 6 with 6 h time duration with fluoride dosage of 50 mg/L. The equilibrium concentration dwindled to 0.4 mg/L at fluoride concentration of 20 mg/L. The Langmuir model designates the adsorption capacity value of 2.15 mg/L with initial fluoride concentration of 0.21 mg/g with R2 value of 0.660. Similarly, the adsorption capacity using Freundlich isotherms is found to be 0.58 L/g and 0.59 L/g with fluoride concentration of 1.84 mg/L and 2.15 mg/L respectively. The results from the present study confirm that coconut fiber possesses appropriate sorption capabilities of fluoride ion but is a pH dependent phenomenon. The outcomes of the study indicate the possible use of cellulose extracted from waste coconut fiber as a low-cost fluoride adsorbent. The present study can be well implemented on real scale systems as it will be beneficial economically as well as environmentally.
    Matched MeSH terms: Hydrogen-Ion Concentration
  18. Jalil M, Annuar MS, Tan BC, Khalid N
    PMID: 25767555 DOI: 10.1155/2015/757514
    Zingiber zerumbet Smith is an important herb that contains bioactive phytomedicinal compound, zerumbone. To enhance cell growth and production of this useful compound, we investigated the growth conditions of cell suspension culture. Embryogenic callus generated from shoot bud was used to initiate cell suspension culture. The highest specific growth rate of cells was recorded when it was cultured in liquid Murashige and Skoog basal medium containing 3% sucrose with pH 5.7 and incubated under continuous shaking condition of 70 rpm for 16 h light and 8 h dark cycle at 24°C. Our results also revealed that the type of carbohydrate substrate, light regime, agitation speed, and incubation temperature could affect the production of zerumbone. Although the zerumbone produced in this study was not abundant compared to rhizome of Z. zerumbet, the possibility of producing zerumbone during early stage could serve as a model for subsequent improvement.
    Matched MeSH terms: Hydrogen-Ion Concentration
  19. Gul Zaman H, Baloo L, Kutty SR, Aziz K, Altaf M, Ashraf A, et al.
    Environ Sci Pollut Res Int, 2023 Jan;30(3):6216-6233.
    PMID: 35989404 DOI: 10.1007/s11356-022-22438-6
    Heavy metal contamination has increased over the globe, causing significant environmental issues owing to direct and indirect releases into water bodies. As a result, metal removal from water entities must be addressed soon. Various adsorbents such as MOFs and chitosan have demonstrated promising results in water treatment. The present study prepared a composite material (chitosan-UiO-66-glycidyl methacrylate MOF) by a microwave-assisted method. The structure and morphology of the chitosan-MOF composite were studied using FE-SEM, EDX, XRD, BET, FT-IR, and TGA techniques. In addition, the adsorption of Pb(II) from aqueous solution onto the chitosan-MOF composite was analyzed in a batch study concerning pH, contact time, initial metal ion concentration, and adsorbent dosage. The composite has a large surface area of 867 m2/g with a total pore volume of 0.51 cm3/g and thermal stability of up to 400 [Formula: see text]. Following an analysis of the adsorption isotherms, kinetics, and thermodynamics, the Langmuir model showed an excellent fit with the adsorption data (R2 = 0.99) and chi-squared (X2 = 3.609). The adsorption process was a spontaneous exothermic reaction and the pseudo-second-order rate equation fitted the kinetic profile well. Moreover, the composite is recyclable, retaining 83.45% of its removal effectiveness after 5 consecutive cycles, demonstrating it as a sustainable adsorbent for metal recovery. This study introduces a novel synthesized composite with enhanced recyclability and a higher potential for eliminating pollutants from industrial wastewater.
    Matched MeSH terms: Hydrogen-Ion Concentration
  20. Islam A, Teo SH, Ahmed MT, Khandaker S, Ibrahim ML, Vo DN, et al.
    Chemosphere, 2021 Jun;272:129653.
    PMID: 33486455 DOI: 10.1016/j.chemosphere.2021.129653
    The contamination of groundwater by arsenic (As) in Bangladesh is the biggest impairing of a population, with a large number of peoples affected. Specifically, groundwater of Gangetic Delta is alarmingly contaminated with arsenic. Similar, perilous circumstances exist in many other countries and consequently, there is a dire need to develop cost-effective decentralized filtration unit utilizing low-cost adsorbents for eliminating arsenic from water. Morphological synthesis of carbon with unique spherical, nanorod, and massive nanostructures were achieved by solvothermal method. Owing to their intrinsic adsorption properties and different nanostructures, these nanostructures were employed as adsorption of arsenic in aqueous solution, with the purpose to better understanding the morphological effect in adsorption. It clearly demonstrated that carbon with nanorods morphology exhibited an excellent adsorption activity of arsenite (about 82%) at pH 3, remarkably superior to the two with solid sphere and massive microstructures, because of its larger specific surface area, enhanced acid strength and improved adsorption capacity. Furthermore, we discovered that iron hydroxide radicals and energy-induced contact point formation in nanorods are the responsible for the high adsorption of As in aqueous solution. Thus, our work provides insides into the microstructure-dependent capability of different carbon for As adsorption applications.
    Matched MeSH terms: Hydrogen-Ion Concentration
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