Displaying publications 461 - 480 of 1243 in total

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  1. Alotaibi AM, Ismail AF
    Int J Environ Res Public Health, 2022 Oct 23;19(21).
    PMID: 36360653 DOI: 10.3390/ijerph192113774
    The natural zeolite has been modified with sulphate and phosphate. The adsorption of thorium from the aqueous solutions by using the natural and modified zeolites has been investigated via a batch method. The adsorbent samples were characterized by X-ray Diffraction (XRD), N2 adsorption-desorption (BET), Fourier transform infrared (FTIR), field emission scanning electron microscopy (FESEM), and energy dispersive X-ray spectroscopy (EDX). Modification of natural zeolite with sulphate and phosphate was found to increase its adsorption capacity of thorium but reduced its specific surface area (SBET). The adsorption experiments were expressed by Langmuir, Freundlich and Dubinin-Radushkevitch (D-R) isotherm models and the results of adsorption demonstrated that the adsorption of thorium onto the natural and modified zeolites correlated better with the Langmuir isotherm model than with the Freundlich isotherm model. The maximum adsorption capacity (Qo) was determined using the Langmuir isotherm model at 25 °C and was found to be 17.27, 13.83, and 10.21 mg/g for phosphate-modified zeolite, sulfate-modified zeolite, and natural zeolite, respectively. The findings of this study indicate that phosphate-modified zeolite can be utilized as an effective and low-cost adsorbent material for the removal of thorium from aqueous solutions.
    Matched MeSH terms: Hydrogen-Ion Concentration
  2. Haq F, Farid A, Ullah N, Kiran M, Khan RU, Aziz T, et al.
    Environ Res, 2022 Dec;215(Pt 1):114241.
    PMID: 36100100 DOI: 10.1016/j.envres.2022.114241
    This study is based on the removal of methylene blue (MB) from aqueous solution by cost effective and biodegradable adsorbent carboxymethyl starch grafted polyvinyl pyrolidone (Car-St-g-PVP). The Car-St-g-PVP was synthesized by grafting vinyl pyrolidone onto carboxymethyl starch by free radical polymerization reaction. The structure and different properties of Car-St-g-PVP were determined by 1H NMR, FT-IR, XRD, TGA and SEM. A series of batch experiments were conducted for the removal of MB, The adsorption affecting factors such as temperature, contact time, initial concentration of MB dye, dose of Car-St-g-PVP and pH were studied in detail. The other parameters like the thermodynamic study, kinetics and isothermal models were fitted to the experimental data. The results showed that pseudo 2nd order kinetics and Langmuir's adsorption isotherms were best fitted to experimental data with regression coefficient R2 viz. 0.99 and 0.97. The kinetic study showed that the adsorption mechanism favored chemisorption. The Gibbs free energy (ΔG°) for the adsorption process was found to be -7.31 kJ/mol, -8.23 kJ/mol, -9.00 kJ/mol and -10.10 kJ/mol at 25 °C, 35 °C, 45 °C and 55 °C respectively. The negative values of ΔG° suggested the spontaneous nature of the adsorption process. Similarly, the positive values of entropy (ΔS°) and enthalpy (ΔH°) 91.27 J/k.mol and 19.90 kJ/mol showed the increasing randomness and endothermic nature of the adsorption process. The value of separation factor (RL) was found to be less than one (RL 
    Matched MeSH terms: Hydrogen-Ion Concentration
  3. Ashrafizadeh M, Delfi M, Zarrabi A, Bigham A, Sharifi E, Rabiee N, et al.
    J Control Release, 2022 Nov;351:50-80.
    PMID: 35934254 DOI: 10.1016/j.jconrel.2022.08.001
    The site-specific delivery of antitumor agents is of importance for providing effective cancer suppression. Poor bioavailability of anticancer compounds and the presence of biological barriers prevent their accumulation in tumor sites. These obstacles can be overcome using liposomal nanostructures. The challenges in cancer chemotherapy and stimuli-responsive nanocarriers are first described in the current review. Then, stimuli-responsive liposomes including pH-, redox-, enzyme-, light-, thermo- and magneto-sensitive nanoparticles are discussed and their potential for delivery of anticancer drugs is emphasized. The pH- or redox-sensitive liposomes are based on internal stimulus and release drug in response to a mildly acidic pH and GSH, respectively. The pH-sensitive liposomes can mediate endosomal escape via proton sponge. The multifunctional liposomes responsive to both redox and pH have more capacity in drug release at tumor site compared to pH- or redox-sensitive alone. The magnetic field and NIR irradiation can be exploited for external stimulation of liposomes. The light-responsive liposomes release drugs when they are exposed to irradiation; thermosensitive-liposomes release drugs at a temperature of >40 °C when there is hyperthermia; magneto-responsive liposomes release drugs in presence of magnetic field. These smart nanoliposomes also mediate co-delivery of drugs and genes in synergistic cancer therapy. Due to lack of long-term toxicity of liposomes, they can be utilized in near future for treatment of cancer patients.
    Matched MeSH terms: Hydrogen-Ion Concentration
  4. Yang F, Jin C, Wang S, Wang Y, Wei L, Zheng L, et al.
    Chemosphere, 2023 May;323:138245.
    PMID: 36841450 DOI: 10.1016/j.chemosphere.2023.138245
    Due to increasing antibiotic pollution in the water environment, green and efficient adsorbents are urgently needed to solve this problem. Here we prepare magnetic bamboo-based activated carbon (MDBAC) through delignification and carbonization using ZnCl2 as activator, resulting in production of an activated carbon with large specific surface area (1388.83 m2 g-1). The influencing factors, such as solution pH, initial sulfadiazine (SD) concentration, temperature, and contact time, were assessed in batch adsorption experiments. The Langmuir isotherm model demonstrated that MDBAC adsorption capacity on SD was 645.08 mg g-1 at its maximum, being higher than majority of previously reported adsorbents. In SD adsorption, the kinetic adsorption process closely followed the pseudo-second kinetic model, and the thermodynamic adsorption process was discovered to be exothermic and spontaneous in nature. The MDBAC exhibited excellent physicochemical stability, facile magnetic recovery and acceptable recyclability properties. Moreover, the synergistic interactions between MDBAC and SD mainly involved electrostatic forces, hydrogen bonding, π-π stacking, and chelation. Within the benefits of low cost, ease of production and excellent adsorption performance, the MDBAC biosorbent shows promising utilization in removing antibiotic contaminants from wastewater.
    Matched MeSH terms: Hydrogen-Ion Concentration
  5. Fahmi AM, Summers S, Jones M, Bowler B, Hennige S, Gutierrez T
    Sci Rep, 2023 Mar 27;13(1):5013.
    PMID: 36973465 DOI: 10.1038/s41598-023-31784-5
    Hydrocarbon-degrading bacteria, which can be found living with eukaryotic phytoplankton, play a pivotal role in the fate of oil spillage to the marine environment. Considering the susceptibility of calcium carbonate-bearing phytoplankton under future ocean acidification conditions and their oil-degrading communities to oil exposure under such conditions, we investigated the response of non-axenic E. huxleyi to crude oil under ambient versus elevated CO2 concentrations. Under elevated CO2 conditions, exposure to crude oil resulted in the immediate decline of E. huxleyi, with concomitant shifts in the relative abundance of Alphaproteobacteria and Gammaproteobacteria. Survival of E. huxleyi under ambient conditions following oil enrichment was likely facilitated by enrichment of oil-degraders Methylobacterium and Sphingomonas, while the increase in relative abundance of Marinobacter and unclassified Gammaproteobacteria may have increased competitive pressure with E. huxleyi for micronutrient acquisition. Biodegradation of the oil was not affected by elevated CO2 despite a shift in relative abundance of known and putative hydrocarbon degraders. While ocean acidification does not appear to affect microbial degradation of crude oil, elevated mortality responses of E. huxleyi and shifts in the bacterial community illustrates the complexity of microalgal-bacterial interactions and highlights the need to factor these into future ecosystem recovery projections.
    Matched MeSH terms: Hydrogen-Ion Concentration
  6. Hamidon TS, Hussin MH
    Int J Biol Macromol, 2023 Apr 01;233:123535.
    PMID: 36740116 DOI: 10.1016/j.ijbiomac.2023.123535
    The present study intended to develop efficient hydrogel spheres in treating simulated wastewater contaminated with p-chlorophenol. Herein, copper-modified nanocellulose was grafted onto alginate to produce eco-friendly hydrogel spheres to utilize as a viable biosorbent. Fabricated spheres were characterized through scanning electron microscopy, thermogravimetry, surface area measurement, point of zero charge and zeta potential analyses. The adsorption of p-chlorophenol was optimized by altering various experimental conditions. Pseudo second order kinetics and Langmuir adsorption isotherm best described the adsorption of p-chlorophenol onto copper-modified cellulose nanocrystal-based spheres. The maximum adsorption capacity was 66.67 mg g-1 with a reusability up to five regeneration cycles. The thermodynamic study directed that p-chlorophenol adsorption was exothermic, spontaneous, and reversible within the analyzed temperature range. Weber-Morris model revealed that intraparticle diffusion was not the singular rate-controlling step in the adsorption process. Hence, copper-modified nanocellulose spheres could be employed as a sustainable and effective biosorbent for p-chlorophenol adsorption from wastewater.
    Matched MeSH terms: Hydrogen-Ion Concentration
  7. Moradi H, Sabbaghi S, Mirbagheri NS, Chen P, Rasouli K, Kamyab H, et al.
    Environ Res, 2023 Apr 15;223:115484.
    PMID: 36775091 DOI: 10.1016/j.envres.2023.115484
    The presence of chloride ion as an environmental pollutant is having a devastating and irreversible effect on aquatic and terrestrial ecosystems. To ensure safe and clean drinking water, it is vital to remove this substance using non-toxic and eco-friendly methods. This study presents a novel and highly efficient Ag NPs-modified bentonite adsorbent for removing chloride ion, a common environmental pollutant, from drinking water using a facile approach. The surface chemical properties and morphology of the pristine Na-bentonite and Ag NPs-Modified bentonite were characterized by field emission scanning electron microscopy (FESEM) and X-ray spectroscopy (EDX), X-Ray diffraction (XRD), Fourier transform infrared (FTIR), and zeta potential (ζ). To achieve maximum chloride ion removal, the effects of experimental parameters, including adsorbent dosage (1-9 g/L), chloride ion concentration (100-900 mg/L), and reaction time (5-25 h), were examined using the Response Surface Methodology (RSM). The chloride ion removal of 90% was obtained at optimum conditions (adsorbent dosage: 7 g/L, chloride ion concentration: 500 mg/L, and reaction time: 20 h). The adsorption isotherm and kinetics results indicated that the Langmuir isotherm model and pseudo-second-order kinetics were found suitable to chloride ion removal. Additionally, the regeneration and reusability of the Ag NPs-modified bentonite were further studied. In the regeneration and reusability study, the Ag NPs-modified bentonite has shown consistently ≥90% and ≥87% chloride ion removal even up to 2 repeated cycles, separately. Thus, the findings in this study provided convincing evidence for using Ag-NPs modified bentonite as a high-efficiency and promising adsorbent to remove chloride ion from drinking water.
    Matched MeSH terms: Hydrogen-Ion Concentration
  8. Fu J, Yap JX, Leo CP, Chang CK
    Int J Biol Macromol, 2023 Apr 15;234:123642.
    PMID: 36791941 DOI: 10.1016/j.ijbiomac.2023.123642
    Although anionic polyelectrolyte hydrogel beads offer attractive adsorption of cationic dyes, phosphate adsorption is limited by electrostatic interactions. In this work, carboxymethyl cellulose (CMC)/sodium alginate (SA) hydrogel beads were modified with calcium carbonate (CaCO3) and/or bentonite (Be). The compatibility between CaCO3 and Be was proven by the homogeneous surface, as shown in the scanning electron microscopic images. Fourier-transform infrared and X-ray diffraction spectra further confirmed the existence of inorganic filler in the hydrogel beads. Although CMC/SA/Be/CaCO3 hydrogel beads attained the highest methylene blue and phosphate adsorption capacities (142.15 MB mg/g, 90.31 P mg/g), phosphate adsorption was significantly improved once CaCO3 nanoparticles were incorporated into CMC/SA/CaCO3 hydrogel beads. The kinetics of MB adsorption by CMC/SA hydrogel beads with or without inorganic fillers could be described by the pseudo-second-order model under chemical interactions. The phosphate adsorption by CMC/SA/Be/CaCO3 hydrogel beads could be explained by the Elovich model due to heterogeneous properties. The incorporation of Be and CaCO3 also improved the phosphate adsorption through chemical interaction since Langmuir isotherm fitted the phosphate adsorption by CMC/SA/Be/CaCO3 hydrogel beads. Unlike MB adsorption, the reusability of these hydrogel beads in phosphate adsorption reduced slightly after 5 cycles.
    Matched MeSH terms: Hydrogen-Ion Concentration
  9. Tamjid Farki NNANL, Abdulhameed AS, Surip SN, ALOthman ZA, Jawad AH
    Int J Phytoremediation, 2023;25(12):1567-1578.
    PMID: 36794599 DOI: 10.1080/15226514.2023.2175780
    Herein, tropical fruit biomass wastes including durian seeds (DS) and rambutan peels (RP) were used as sustainable precursors for preparing activated carbon (DSRPAC) using microwave-induced H3PO4 activation. The textural and physicochemical characteristics of DSRPAC were investigated by N2 adsorption-desorption isotherms, X-ray diffraction, Fourier transform infrared, point of zero charge, and scanning electron microscope analyses. These findings reveal that the DSRPAC has a mean pore diameter of 3.79 nm and a specific surface area of 104.2 m2/g. DSRPAC was applied as a green adsorbent to extensively investigate the removal of an organic dye (methylene blue, MB) from aqueous solutions. The response surface methodology Box-Behnken design (RSM-BBD) was used to evaluate the vital adsorption characteristics, which included (A) DSRPAC dosage (0.02-0.12 g/L), (B) pH (4-10), and (C) time (10-70 min). The BBD model specified that the DSRPAC dosage (0.12 g/L), pH (10), and time (40 min) parameters caused the largest removal of MB (82.1%). The adsorption isotherm findings reveal that MB adsorption pursues the Freundlich model, whereas the kinetic data can be well described by the pseudo-first-order and pseudo-second-order models. DSRPAC exhibited good MB adsorption capability (118.5 mg/g). Several mechanisms control MB adsorption by the DSRPAC, including electrostatic forces, π-π stacking, and H-bonding. This work shows that DSRPAC derived from DS and RP could serve as a viable adsorbent for the treatment of industrial effluents containing organic dye.
    Matched MeSH terms: Hydrogen-Ion Concentration
  10. Francis AO, Kevin OS, Ahmad Zaini MA
    Int J Phytoremediation, 2023;25(12):1625-1635.
    PMID: 36823750 DOI: 10.1080/15226514.2023.2179013
    This study evaluated the characteristics of zinc chloride modified vitex doniana seed activated carbon (VDZnCl2) for the removal of methylene blue. VDZnCl2 was characterized for textural properties, surface morphology and surface chemistry. Batch adsorption of methylene blue by VDZnCl2 was evaluated for the effects of concentration, contact time, adsorbent dosage, and solution pH. The surface area increased from 14 to 933 m2/g with porous texture to facilitate adsorption. The SEM micrograph showed varieties of pores with widened cavities. The FTIR spectra showed the characteristics of O-H and C=C groups commonly found in carbonaceous materials. The maximum methylene blue adsorption was recorded as 238 mg/g at concentration range of 1-800 mg/L and VDZnCl2 dosage of 50 mg. Sips isotherm fitted well with the equilibrium data, suggesting that the adsorption by VDZnCl2 was a physical process onto its heterogeneous surface, while the applicability of pseudo-first-order kinetics implies that external diffusion was the rate controlling mechanism. The performance put up by VDZnCl2 suggested that it is a potential adsorbent substitute for dye wastewater treatment.
    Matched MeSH terms: Hydrogen-Ion Concentration
  11. Alqarni LS, Algethami JS, El Kaim Billah R, Alorabi AQ, Alnaam YA, Algethami FK, et al.
    Int J Biol Macromol, 2024 Apr;263(Pt 2):129989.
    PMID: 38354916 DOI: 10.1016/j.ijbiomac.2024.129989
    In this study, the synthesis and experimental theoretical evaluation of a new chitosan/alginate/hydrozyapatite nanocomposite doped with Mn2 and Fe2O3 for Cr removal was reported. The physicochemical properties of the obtained materials were analyzed using the following methods: SEM-EDX, XRD, FTIR, XPS, pH drift measurements, and thermal analysis. The adsorption properties were estimated based on equilibrium and adsorption kinetics measurements. The Langmuir, Freundlich and Temkin isotherms were applied to analyze the equilibrium data. The thermodynamic analysis of adsorption isotherms was performed. A number of equations and kinetic models were used to describe the adsorption rate data, including pseudo-first (PFOE) and pseudo-second (PSOE) order kinetic equations. The obtained test results show that the synthesized biomaterial, compared to pure chitosan, is characterized by greater resistance to high temperatures. Moreover, this biomaterial had excellent adsorption properties. For the adsorption of Cr (VI), the equilibrium state was reached after 120 min, and the sorption capacity was 455.9 mg/g. In addition, DFT calculations and NCI analyses were performed to get more light on the adsorption mechanism of Cr (VI) on the prepared biocomposite.
    Matched MeSH terms: Hydrogen-Ion Concentration
  12. Raj ST, Puspanadan S, Gan CY, Tan JS
    Int J Biol Macromol, 2024 May;267(Pt 2):131376.
    PMID: 38608981 DOI: 10.1016/j.ijbiomac.2024.131376
    Diabetes is a chronic, metabolic disease characterized by hyperglycemia resulting from either insufficient insulin production or impaired cellular response to insulin. Exopolysaccharides (EPS) produced by Lactobacillus spp. demonstrated promising therapeutic potential in terms of their anti-diabetic properties. Extraction and purification of EPS produced by Lactobacillus acidophilus and Limosilactobacillus reuteri were performed using ethanol precipitation, followed by alcohol/salt based aqueous two-phase system (ATPS). The purification process involved ethanol precipitation followed by an alcohol/salt-based ATPS. The study systematically investigated various purification parameters in ATPS, including ethanol concentration, type and concentration of ionic liquid, type and concentration of salt and pH of salt. Purified EPS contents from L. acidophilus (63.30 μg/mL) and L. reuteri (146.48 μg/mL) were obtained under optimum conditions of ATPS which consisted of 30 % (w/w) ethanol, 25 % (w/w) dipotassium hydrogen phosphate at pH 10 and 2 % (w/w) 1-butyl-3-methylimidazolium octyl sulfate. The extracted EPS content was determined using phenol sulphuric acid method. In α-amylase inhibition tests, the inhibitory rate was found to be 92.52 % (L. reuteri) and 90.64 % (L. acidophilus), while in α-glucosidase inhibition tests, the inhibitory rate was 73.58 % (L. reuteri) and 68.77 % (L. acidophilus), based on the optimized parameters selected in ATPS. These results suggest that the purified EPS derived from the postbiotics of Lactobacillus spp. hold promise as potential antidiabetic agents.
    Matched MeSH terms: Hydrogen-Ion Concentration
  13. Gul S, Ahmad Z, Asma M, Ahmad M, Rehan K, Munir M, et al.
    Chemosphere, 2022 Nov;307(Pt 1):135633.
    PMID: 35810866 DOI: 10.1016/j.chemosphere.2022.135633
    Cadmium (Cd) and Lead (Pb) from industrial wastewater can bioaccumulate in the living organisms of water bodies, posing serious threats to human health. Therefore, efficient remediation of heavy metal ions of Cd (II) and Pb (II) in aqueous media is necessary for public health and environmental sustainability. In the present study, water stable Zirconium (Zr) based metal organic frameworks (MOFs) with SO3H functionalization were synthesized by solvothermal method and used first time for the adsorption of Cd (II) and Pb (II). Synthesis of UiO-66-SO3H, nano-sized (<100 nm) MOFs, was confirmed by FTIR, XRD, FESEM and BET. Effects of contact time, pH and temperature were investigated for adsorption of Cd (II) and Pb (II) onto SO3H-functionalized Zr-MOFs. The UiO-66-SO3H displayed notable rejections of 97% and 88% towards Cd (II) and Pb (II), respectively, after 160 min at 25 °C and pH (6) with an initial concentration of 1000 mg/L. Adsorption capacities of Cd (II) and Pb (II) were achieved as 194.9154 (mg/g) and 176.6879 (mg/g), respectively, at an initial concentration of 1000 mg/L. The Pseudo second-order kinetic model fitted well with linear regression (R2) of value 1. The mechanism was confirmed mainly as a chemisorption and coordination interaction between sulfone group (-SO3H) and metal ions Cd (IIa) and Pb (II). These results may support effective adsorption and can be studied further to enrich and recycle other heavy metals from wastewater.
    Matched MeSH terms: Hydrogen-Ion Concentration
  14. Vijayasree VP, Abdul Manan NS
    Int J Biol Macromol, 2024 Oct;277(Pt 1):134103.
    PMID: 39047997 DOI: 10.1016/j.ijbiomac.2024.134103
    Organic anionic dyes are major water pollutants due to their low degradability caused by complex aromatic structures. Not only do they exert toxic, mutagenic, teratogenic, tumorigenic, and genotoxic effects, but they also decrease fertility and cause irritation to the skin and respiratory system in humans. This long-term toxicity has detrimental effects on aquatic organisms and their surroundings, resulting in an imbalanced ecosystem. In this study, a Cs@Fe3O4 magnetic biosorbent was synthesised to uptake three anionic dyes and characterised for FTIR, BET/BJH, XRD, TGA, VSM, and FESEM analyses. The biosorbent average surface area was confirmed to be 52.6524 m2/g, with average pore sizes of 7.3606 nm and 6.9823 nm for adsorption-desorption processes, respectively. Batch adsorption studies pH values, contact times, temperature, initial dye concentrations, and adsorbent dosages were examined. Several isotherm and kinetic models were studied to determine the adsorption mechanism. The adsorption data of these dyes at equilibrium was observed to match Langmuir's isotherm and pseudo-second-order kinetic models. The thermodynamic study revealed that the adsorption process for these dyes was an exothermic reaction. Maximum adsorption capacities for congo red, methyl orange, and metanil yellow were 117.77 mg/g, 137.77 mg/g, and 155.57 mg/g, respectively. The reusability of recovered Cs@Fe3O4 after dye adsorption was evaluated up to five continuous adsorption-desorption cycles for its possible industrial applications.
    Matched MeSH terms: Hydrogen-Ion Concentration
  15. Reghioua A, Atia D, Hamidi A, Jawad AH, Abdulhameed AS, Mbuvi HM
    Int J Biol Macromol, 2024 Apr;263(Pt 1):130304.
    PMID: 38382796 DOI: 10.1016/j.ijbiomac.2024.130304
    This present work targets the production of an eco-friendly adsorbent (hereinafter KA/CEL) from kaolin clay functionalized with cellulose extract obtained from peanut shells. The adsorbents were used for decolorization of two different types of organic dyes (cationic: methylene blue, MB; anionic: Congo red, CR) from an aqueous environment. Several analytical methods, including Brunauer-Emmett-Teller (surface properties), Fourier Transforms infrared (functionality), scanning electron microscope, Energy dispersive X-Ray (morphology), and pHpzc test (surface charge), were used to attain the physicochemical characteristics of KA/CEL. The Box-Behnken Design (BBD) was applied to determine the crucial factors affecting adsorption performance. These included cellulose loading at 25 %, an adsorbent dose of 0.06 g, solution pH set at 10 for MB and 7 for CR, a temperature of 45 °C, and contact times of 12.5 min for MB and 20 min for CR dye. The adsorption data exhibited better agreement with the pseudo-second-order kinetic and Freundlich models. The Langmuir model estimated the monolayer capacity to be 291.5 mg/g for MB and 130.7 mg/g for CR at a temperature of 45 °C. This study's pivotal finding underscores the promising potential of KA/CEL as an effective adsorbent for treating wastewater contaminated with organic dyes.
    Matched MeSH terms: Hydrogen-Ion Concentration
  16. Fu J, Yap JX, Leo CP, Chang CK
    Int J Biol Macromol, 2024 Aug;274(Pt 2):133510.
    PMID: 38960270 DOI: 10.1016/j.ijbiomac.2024.133510
    The biodegradable, nontoxic, and renewable carboxymethyl cellulose (CMC) hydrogel has been developed into a green adsorbent. However, the weak chemical interaction limits its adsorption capability and reusability. This work incorporated lignin with complex structure and ZnO nanoparticles with photocatalytic properties into CMC hydrogel beads to improve the removal of methylene blue (MB) through chemical interaction. Scanning electron microscopic images and Fourier-transform infrared spectra confirmed the compatibility between lignin and ZnO nanoparticles as well as the increment of active sites for dye removal. The MB adsorption on CMC hydrogel beads was more significantly affected by the temperate and initial concentration compared to contact time, pH, and adsorbent dosage. The MB adsorption capacity of CMC hydrogel was improved to 276.79 mg/g after incorporating lignin and ZnO nanoparticles. The adsorption followed the pseudo-second-order kinetic model and Langmuir isotherm model, indicating chemical adsorption. After 6 cycles, the adsorption capacity was reduced by about 15 %. The UV irradiation could recover and improve MB adsorption capacity of CMC hydrogel beads containing ZnO nanoparticles due to the introduction of reactive oxygen species.
    Matched MeSH terms: Hydrogen-Ion Concentration
  17. Malik MK, Kumar V, Kumarasamy V, Singh OP, Kumar M, Dixit R, et al.
    Molecules, 2024 Jul 05;29(13).
    PMID: 38999160 DOI: 10.3390/molecules29133208
    Chemically modified mandua starch was successfully synthesized and applied to coat mesalamine-loaded matrix tablets. The coating material was an aqueous dispersion of mandua starch modified by sodium trimetaphosphate and sodium tripolyphosphate. To investigate the colon-targeting release competence, chemically modified mandua starch film-coated mesalamine tablets were produced using the wet granulation method followed by dip coating. The effect of the coating on the colon-targeted release of the resultant delivery system was inspected in healthy human volunteers and rabbits using roentgenography. The results show that drug release was controlled when the coating level was 10% w/w. The release percentage in the upper gastric phase (pH 1.2, simulated gastric fluid) was less than 6% and reached up to 59.51% w/w after 14 h in simulated colonic fluid. In addition to in vivo roentgenographic studies in healthy rabbits, human volunteer studies proved the colon targeting efficiency of the formulation. These results clearly demonstrated that chemically modified mandua starch has high effectiveness as a novel aqueous coating material for controlled release or colon targeting.
    Matched MeSH terms: Hydrogen-Ion Concentration
  18. Tong ZX, Oh WD
    Int J Biol Macromol, 2024 Oct;277(Pt 3):134453.
    PMID: 39098691 DOI: 10.1016/j.ijbiomac.2024.134453
    Chitosan possesses electron-rich amino (-NH2) and hydroxyl (-OH) moieties which can anchor with transition metal ions during synthesis. Herein, chitosan was employed as an additive to prepare bismuth ferrite (BFO) via hydrothermal approach. The characterization studies revealed that adding chitosan during BFO synthesis leads to the creation of more oxygen vacancies. The performance of chitosan modified BFO (CMB) was evaluated as peroxymonosulfate (PMS) activator for ciprofloxacin (CIP) removal. Apparently, the addition of 10 wt% chitosan during BFO synthesis (CMB-10) resulted in 1.7 times increase of performance compared to the pristine BFO. Increasing the catalyst loading and PMS dosage resulted in positive effect with 5.7 and 1.9 times rate enhancement, respectively. The CMB-10 exhibited tolerance against pH variation, water matrix, and interfering species. The scavenging experiments indicated that singlet oxygen (1O2), superoxide radicals (O2•-) and sulfate radicals (SO4•-) played a major role in CIP degradation. These reactive oxygen species were generated from PMS activation via Fe3+/Fe2+ and Bi5+/Bi3+ coupling, and oxygen vacancies on the catalyst surface. The CIP degradation pathways were also elucidated based on the detected CIP intermediates. Overall, this study provides insights into the use of chitosan to prepare sustainable materials for pollutants removal via PMS activation.
    Matched MeSH terms: Hydrogen-Ion Concentration
  19. Elsayed N
    Int J Pharm, 2024 Dec 05;666:124819.
    PMID: 39424084 DOI: 10.1016/j.ijpharm.2024.124819
    Lung inflammation involves the activation of immune cells and inflammatory mediators in response to injury and infection. When inflammation persists, fibroblasts, which are resident lung cells, become activated, leading to pulmonary fibrosis (PF), abnormal wound healing, and long-term damage to the alveolar epithelium. This persistent inflammation and fibrosis can also elevate the risk of lung cancer, emphasizing the need for innovative treatments. Current therapies, such as inhaled corticosteroids (ICS) and chemotherapy, have significant limitations. Although conventional nanoparticles (NPs) provide a promising avenue for treating lung disorders, they have limited selectivity and stability. Polyethylene glycol (PEG) grafting can prevent NP aggregation and phagocytosis, thus prolonging their circulation time. When combined with targeting ligands, PEGylated NPs can deliver drugs precisely to specific cells or tissues. Moreover, pH-sensitive NPs offer the advantage of selective drug delivery to inflammatory or tumor-acidic environments, reducing side effects. These NPs can change their size, shape, or surface charge in response to pH variations, improving drug delivery efficiency. This review examines the techniques of PEGylation, the polymers used in pH-sensitive NPs, and their therapeutic applications for lung inflammation, fibrosis, and cancer. By harnessing innovative NP technologies, researchers can develop effective therapies for respiratory conditions, addressing unmet medical needs and enhancing patient outcomes.
    Matched MeSH terms: Hydrogen-Ion Concentration
  20. Wang L, Chen X, Xi X, Lee SH, Lum WC, Huang Y, et al.
    Int J Biol Macromol, 2024 Dec;282(Pt 6):137438.
    PMID: 39528202 DOI: 10.1016/j.ijbiomac.2024.137438
    Condensed tannin was solidified onto chitosan microspheres to prepare chitosan-tannin (CT) composite microspheres with a simple preparation method to study its performance in adsorbing copper (Cu2+) and lead ions (Pb2+) in aqueous media. The study investigated the influence of the mass ratio of tannin and chitosan, pH value, adsorption time, and initial concentrations of Cu2+ and Pb2+ on the adsorption capacity of Cu2+ and Pb2+ ions. Additionally, the study examined the adsorption isotherms and kinetics of Cu2+ and Pb2+ on CT composite microspheres. The adsorption process aligns more closely with the fitting results of the Langmuir model. The maximum capacity for saturated monolayer adsorption of CT composite microspheres for Cu2+ and Pb2+ was 37.6 and 52.9 mg/g, respectively. The adsorption process of CT composite microspheres for Cu2+ and Pb2+ was primarily driven by single-layer chemical adsorption. In addition, metal ions adsorbed onto CT composite microspheres can be released by treating them with a dilute solution of strong acid. Furthermore, the CT composite microspheres exhibited impressive removal efficiencies of 82 % and 95 % for Cu2+ and Pb2+ respectively, even at low concentrations of 2 mg/L. The CT composite microspheres have the ability to easily separate the adsorbed Cu2+ and Pb2+ ions.
    Matched MeSH terms: Hydrogen-Ion Concentration
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