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•A new polycation PVBTAC-modified ZnO/SiO2 nanocomposite based on rice husk was successfully fabricated.•The optimum conditions for DCF removal using PVBTAC-modified ZnO/SiO2 were ...contact time 90 min, pH 8 and dosage 10 mg/mL.•The maximum adsorption capacity of DCF was 66 mg/g and the removal efficiency was 91.8%.•After four regenerations, the DCF removal using PVBTAC modified ZnO/SiO2 was still greater than 84%.•The E.coli removal was greater than 88 % that was controlled by electrostatic and non-electrostatic interactions.
The present study investigated the adsorptive removal of non-steroidal medication diclofenac (DCF) using polycation, PVBTAC modified zinc oxide/silica nanocomposite (ZnO/SiO2). The ZnO/SiO2 which was fabricated based on nanosilica rice, was examined by XRD, FT-IR, TEM, EDX, and zeta potential measurements. Surface of ZnO/SiO2 was modified by PVBTAC adsorption at pH 9 and 100 mM KCl to reverse the high charge of material. The optimum parameters for DCF removal using PVBTAC-modified ZnO/SiO2 were contact time 90 min, pH 8 and adsorbent dosage 10 mg/mL. The maximum adsorption capacity and the removal efficiency of DCF were found to be 66 mg/g and 91.8%, respectively, while the bacteria Escherichiacoli(E.coli) removal reached greater than 88 %. Adsorption of DCF on PVBTAC-modified ZnO/SiO2 was mainly controlled by electrostatic attraction between anionic DCF molecules and positively charged PVBTAC-modified ZnO/SiO2 surface whereas the E.coli removal was controlled by both electrostatic and non-electrostatic interactions. Adsorption isotherms of DCF on PVBTAC-modified ZnO/SiO2 at different ionic strengths were reasonably represented by a two-step model while adsorption kinetics fitted well with the pseudo-second-order model. After four regenerations of PVBTAC modified ZnO/SiO2, the DCF removal still exceeded 84%. Our materialis agreat performance adsorbent to remove pharmaceutical and bacteria.
We report the first study of adsorption of a strong polycation, poly(3-methacryloylamino propyl-trimethylammonium chloride) (PMAPTAC) on nanosilica (nano-SiO2) extracted from rice husk. PMAPTAC was ...successfully synthesized and characterized by 1H-nuclear magnetic resonance (1H NMR) and gel-permeation chromatography (GPC) methods. PMAPTAC characteristics were found to be Mn = 1.61 × 105, Mw = 2.16 × 106, Mw/Mn = 13.4. Beta-lactam cefixime (CEF) removal was dramatically enhanced after polymer coating by pre-adsorption of PMAPTAC on nano-SiO2. The new adsorbent was dubbed PMAPTAC coated nano-SiO2 (PCNS). Required time for adsorption, PCNS dosage, pH, and KCl concentration were thoroughly optimized for CEF removal and achieved at 120 min, 10 mg/mL, 4, and 1 mM, respectively. A two-step model can be used to fit the PMAPTAC on nano-SiO2 and CEF on PCNS isotherms at different ionic strengths. Adsorption kinetics of CEF on PCNS appears to be pseudo-second-order. CEF removal using PCNS reached 89%, saturating at 10.9 mg/g. The driving force for CEF adsorption on PCNS was primarily Coulombic interaction of negative CEF species and positive surface charge of PCNS. After three reuses, CEF elimination was still greater than 85%. The influence of some organics on CEF treatment using PCNS was insignificant while CEF removal from a real hospital wastewater sample was greater than 70%. Our study indicates that a hybrid and new adsorbent based on nano-SiO2 rice husk with pre-adsorption with PMAPTAC is useful for antibiotic removal from wastewater.
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•Synthesized PMAPTAC coated nanosilica forms highly positive charge PCNS as a novel adsorbent.•The treatment of antibiotic cefixime (CEF) reached 90 % with pH 4, time for adsorption 120 min, and dosage of PCNS 10 mg/mL.•Adsorption isotherm of CEF was in accordance with two-step model while adsorption kinetic was well fitted by pseudo-second-order model.•The treatment of CEF using PCNS was greater than 85% after three regenerations.
This study aims to investigate the adsorption characteristics of cationic surfactant, cetyltrimethylamonium bromide (CTAB) onto negatively nanosilica rice husk surface and the application for ...antibiotic treatment in water environment. Adsorption of CTAB onto nanosilica increased with an increase of solution pH, due to an enhancement of the electrostatic attraction between cationic methylamomethylamonium groups and negatively charged nanosilica surface enhanced at higher pH. Adsorption of CTAB decreased with a decrease of ionic strength while a common intersection point (CIP) was observed for adsorption isotherm at different ionic strengths, suggesting that hydrophobic interactions between alkyl chains in CTAB molecules significantly induced adsorption and admicelles with bilayer formation were dominant than monolayer of hemimicelles. The CTAB functionalized nanosilica (CFNS) was applied for removal of beta-lactam amoxicillin (AMX). The best conditions for AMX treatment using CFNS were selected as pH 10, contact time 60 min and CFNS dosage 10 mg/mL. Removal efficiency of AMX using CFNS reached to 100% under optimum conditions while it was only 25.01% using nanosilica without CTAB. The maximum AMX adsorption capacity using CFNS of about 25 mg/g was much higher than other adsorbents. The effects of different organics such as humic acid, anionic surfactant, and other antibiotics on AMX removal using CFNS were also studied. A two-step model can fit CTAB uptake isotherms onto nanosilica and AMX onto CFNS well at different KCl concentrations. Based on the desorption of CTAB with AMX adsorption as well as adsorption isotherms, the change in surface charge and functional vibration groups after adsorption, we indicate that AMX adsorption onto CFNS was mainly controlled by electrostatic interaction. We reveal that CFNS is an excellent adsorbent for antibiotic treatment from aqueous solution.
•CTAB functionalized nanosilica rice husk (CFNS) is an excellent adsorbent for beta-lactam amoxicillin (AMX) removal.•Adsorption of CTAB onto nanosilica followed local bilayer of admicelle than hemimicelle monolayer.•Maximum AMX adsorption capacity using CFNS and removal efficiency were 25 mg/g and 100%, respectively.•Adsorption isotherms of CTAB onto nanosilica and AMX onto CFNS were fitted well by two-step model.•The AMX adsorption onto CFNS was mainly controlled by electrostatic attraction.
A novel core–shell nanomaterial, ZnO@SiO2, based on rice husk for antibiotic and bacteria removal, was successfully fabricated. The ZnO@SiO2 nanoparticles were characterized by X-ray diffraction ...(XRD), energy-dispersive X-ray spectroscopy (EDX), Fourier transform infrared (FTIR) spectroscopy, transmission electron microscopy (TEM), photoluminescence spectroscopy (PL), Brunauer–Emmett–Teller (BET) method, diffuse reflectance ultraviolet–vis (DR-UV–vis) spectroscopy, X-ray photoelectron spectroscopy (XPS), Raman spectroscopy, and ζ-potential measurements. β-Lactam antibiotic amoxicillin (AMX) was removed using ZnO@SiO2 nanoparticles with an efficiency greater than 90%, while Escherichia coli removal was higher than 91%. The optimum effective conditions for AMX removal using ZnO@SiO2, including solution pH, adsorption time, and ZnO@SiO2 dosage, were 8, 90 min, and 25 mg/mL, respectively. The maximum adsorption capacity reached 52.1 mg/g, much higher than those for other adsorbents. Adsorption isotherms of AMX on ZnO@SiO2 were more in accordance with the Freundlich model than the Langmuir model. The electrostatic attraction between negative species of AMX and the positively charged ZnO@SiO2 surface induced adsorption, while the removal of E. coli was governed by both electrostatic and hydrophobic interactions. Our study demonstrates that ZnO@SiO2 based on rice husk is a useful core–shell nanomaterial for antibiotic and bacteria removal from water.
A method for the simultaneous determination of seven B-group vitamers including thiamine, riboflavin, nicotinamide, niacin, pyridoxine, pyridoxal, and pyridoxamine in nutritional products by using ...enzymatic digestion followed by LC-MS/MS quantification was studied. The LC-MS/MS conditions such as MS transitions, mobile phase programs, and ammonium formate buffer concentrations, and sample treatment procedures (e.g., concentrations of buffer solution, digestion temperature, and digestion time) were investigated. The analytical method performance was evaluated by multiple criteria such as selectivity, linearity, detection and quantification limits, repeatability, reproducibility, and recovery by using real sample matrices. The validated method was successfully applied to analyze vitamin B concentrations in different nutritional products like ultra-heat-treated milk, powdered milk, and nutritional powder. Vitamin B concentrations varied over a wide range from lower than detection limits to about 9000 µg/100 g, depending on vitamin groups, compound forms, and sample types. The measured concentrations of B-group vitamins in our samples were generally in good agreement with values of label claims.
The objective of the present study is to investigate removal of cationic dye, rhodamine B (RhB), in water environment using a high-performance absorbent based on metal oxide nanomaterials toward ...green chemistry. The adsorption of sodium dodecyl sulfate (SDS) onto synthesized alpha alumina (α-Al2O3) material (M0) at different ionic strengths under low pH was studied to fabricate a new adsorbent as SDS-modified α-Al2O3 material (M1). The RhB removal using M1 was much higher than M0 under the same experimental conditions. The optimal conditions for RhB removal using M1 were found to be contact time 30 min, pH 4, and adsorbent dosage 5 mg/mL. The maximum RhB removal using M1 achieved 100%, and adsorption amount reached 52.0 mg/g. Adsorption isotherms of RhB onto M1 were well fitted by the two-step adsorption model. The electrostatic attraction between positive RhB molecules and negatively charged M1 surface controlled the adsorption that was evaluated by the surface charge change with zeta potential and adsorption isotherms. Very high RhB removal of greater than 98% after four regenerations of M1 and the maximum removal for all actual textile wastewater samples demonstrate that SDS-modified nano α-Al2O3 is a high-performance and reusable material for RhB removal from wastewater.
Adsorption of essential amino acid, Tryptophan (Tryp) on synthesized gibbsite nanoparticles and their applications in eliminating of antibiotic ciprofloxacin (CFX) and bacteria Escherichia coli (E. ...coli) in aqueous solution. Nano-gibbsite which was successfully fabricated, was characterized by XRD, TEM-SAED, FT-IR, SEM-EDX and zeta potential measurements. The selected parameters for Tryp adsorption on nano-gibbsite to form biomaterial, Tryp/gibbsite were pH 11, gibbsite dosage 20 mg/mL and 1400 mg/L Tryp. The optimum conditions for CFX removal using Tryp/gibbsite were adsorption time 60 min, pH 5, and 20 mg/mL Tryp/gibbsite dosage. The CFX removal significantly raised from 63 to 90% when using Tryp/gibbsite. The Freundlich and pseudo-second-order models achieved the best fits for CFX adsorption isotherm and kinetic on Tryp/gibbsite, respectively. The amount of CFX increased with increasing ionic strength, suggesting that both electrostatic and non-electrostatic interactions were important. After four reused time, CFX removal was greater than 66%, demonstrating that Tryp/gibbsite is reusable with high performance in removing CFX. The application in bacterial activity in term of E. coli reached greater than 98% that was the best material for bacteria inactivation. The present study reveals that Tryp/gibbsite is an excellent bio-material for removing CFX and E. coli.
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•New bio-adsorbed based on Tryptophan coated nano-gibbsite (Tryp/gibbsite) was successfully synthesized.•The optimum conditions for CFX removal using Tryp/gibbsite were contact time 90 min, pH 5, and 20 mg/mL adsorbent dosage.•The highest CFX removal using Tryp/gibbsite reached 90 % while 66 % removal was achieved after four regenerations.•The Tryp adsorption on nano-gibbsite was by non-electrostatic, CFX adsorption on Tryp/gibbsite was governed by electrostatic interactions.•The E. coli removal was greater than 98 % that was much higher than other nanomaterials.
•Lysozyme protein adsorption on nanosilica was controlled by both electrostatic and non-electrostatic interactions.•The lysozyme modified nanosilica (LMNS) increased LFX removal dramatically from ...51.51% to 80.63%.•Optimum conditions for LFX removal were pH 8.0, contact time 90 min, adsorbent dosage 10 mg/mL.•Adsorption of LFX on LMNS was mainly governed by electrostatic attraction.•The removal efficiencies of E.coli and Bacillus removal using LMNS were greater than 90 %.
In this paper, we studied adsorption of protein lysozyme on nanosilica and their applications for removal of levofloxacin (LFX) antibiotic and bacteria Escherichiacoli(E.coli) and Bacillus in water environment. Solution pH 10, contact time 120 min, nanosilica dosage 10 mg/mL and 1 mM KCl were the best conditions for lysozyme adsorption on nanosilica to form biomaterial, namely lysozyme modified nanosilica (LMNS). The optimal parameters for the removal of LFX using LMNS were determined to be 90 min of adsorption time, pH 8, and 10 mg/ml of adsorbent. Adsorptive removal of LFX dramatically increased in ideal circumstances, going from 51.51% to 80.63% when using LMNS. Two-step and Freundlich models were used to represent isothermal adsorption of LFX on LMNS at different strengths while a pseudo-second-order achieved the best fit for LFX adsorption kinetic on LMNS. The amount of LFX that adsorbs to LMNS reduced as salt concentration increased, suggesting that electrostatic interaction was primarily responsible for the adsorption. After four regenerations, LFX removal was greater than 60%, proving that LMNS is highly effective in removing LFX. The removal of E.coli and Bacillus were reached greater than 90 % that were much higher than other materials. Both electrostatic and hydrophobic interactions governed the removal of E.coli and Bacillus. Our results indicate that LMNS is an excellent bio-adsorbent for removal of antibiotic and bacteria in aqueous solution.
In this study, we report the development of versatile and cost-effective analytical approaches for analysis and quality control of different nutraceutical and tonic products, using capillary ...electrophoresis (CE) coupled with contactless conductivity detection (C4D). Insights into CE-C4D instrumental designs that are adapted to the context in developing countries are provided. A highlight was made for quality control of vitamins, glucosamine and some minerals in different nutraceutical formulations collected from pharmacies in Vietnam. The lowest detection limit (LOD) achieved with the developed methods was 0.1 mg/L for vitamins, using the optimized background electrolyte (BGE) composed of 12 mM arginine (Arg)/acetic acid (AcOH) at pH 7.5 with 10 % acetonitrile (ACN). For magnesium and B6, the optimized CE-C4D conditions with the BGE composed of 10 mM Arg/AcOH (pH 5) with 20 % ACN allows its detection down to 0.05 mg/L. For glucosamine and calcium, the best performance with LOD of 0.05 mg/L was achieved with BGE composed of 10 mM Tris/AcOH (pH 5). Good agreement between results from CE-C4D and the confirmation methods was achieved for all investigated compounds, with their result deviations less than 15 %.
•An inexpensive and simple tool for quality control of nutraceutical products is proposed.•New CE-C4D methods for analyses of vitamins, glucosamine and magnesium supplements have been developed.•Quality control of tonic products was implemented with new CE- C4D and reference methods.
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