•Carboxylated cellulose nanocrystal (CCN)-sodium alginate hydrogel beads were prepared.•CCN-Alg beads were used for Pb(II) adsorption from aqueous solution.•This adsorbent is efficient, recyclable, ...and environmentally friendly.•Experimental data were fitted to kinetic, thermodynamic, and isotherm models.
Carboxylated cellulose nanocrystal-sodium alginate (CCN-Alg) hydrogel beads were easily prepared through a cross-linking method. The structure and properties of the composite beads were characterized by TEM, FTIR, SEM, XPS, thermogravimetric analysis (TGA), and zeta potential measurement. A high ratio of 76% of the Pb(II) ion was adsorbed within the first 2h, and the adsorption equilibrium was nearly reached after 3h. The experimental isotherm could be fitted by the Langmuir model, yielding an extreme adsorption capacity of 338.98mgg−1. The adsorption process followed a pseudo-second-order kinetic model, and thermodynamic analyses confirmed that the adsorption is a spontaneous and endothermic process. Regeneration tests with acid treatment indicated that the CCN-Alg beads performed well in repeated Pb(II) adsorptions, as they could maintain an adsorption capacity of 223.2mgg−1 after five repeated cycles. These results indicate that these CCN-Alg beads are a potentially effective and sustainable adsorbent for application in wastewater treatment.
•Alginate oligosaccharide (AOS) was used to stabilize zein nanoparticles.•Zein-AOS nanoparticles were relatively stable under different pH and temperatures.•The encapsulation efficiency of zein-AOS ...nanoparticles was fairly good.
In this study, zein was stabilized using alginate oligosaccharides (AOS) for the delivery of curcumin (Cur) through antisolvent precipitation. Zein-AOS2:1 nanoparticles were uniform and stable (size 116.5 nm, polydispersity index (PDI) 0.16, charge −30 mV). The complex nanoparticle system was relatively stable under different conditions, including pH 4–9 and temperature 30–90 °C. In addition, the encapsulation efficiency of the Cur/zein-AOS2:1 complex nanoparticles was 89.7%. Zein was protected during gastrointestinal digestion. Only 32.9% Cur was released in the stomach after 90 min and 83.8% was released in the intestinal tract after 240 min proving that zein-AOS complex nanoparticles showed a good sustained-release effect. Thus, the zein-AOS complex nanoparticle system is suitable for delivering encapsulated lipophilic bioactive compounds.
Chitosan modification is an important method for the development of adsorbents that has attracted considerable interest in recent years. In this regard, a new type of efficient Pb(II) adsorbent was ...prepared in a simple and cost-effective way. In this study, carboxylated chitosan (CYCS) and carboxylated nanocellulose (CNC) were used to chelate and synthesize hydrogel spheres with effective adsorption sites, in calcium chloride solution. The prepared carboxylated chitosan/carboxylated nanocellulose (CYCS/CNC) hydrogel beads were used as Pb(II) adsorbents, and using scanning electron microscopy, Fourier transform infrared spectroscopy, and X-ray photoelectron spectroscopy, the structure and adsorption properties of the prepared beads were investigated. The CYCS/CNC adsorbents exhibited an excellent aqueous Pb(II) adsorption capacity (qm = 334.92 mg g−1), and the experimental results further revealed that the adsorption data fitted well with the Langmuir model, and the adsorption kinetics accorded with the pseudo-second-order model. Additionally, the adsorption mechanism was identified as monolayer chemisorption.
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•Efficient and economic CYCS/CNC composite is prepared for Pb(II) adsorption.•CYCS/CNC exhibits excellent aqueous Pb(II) adsorption capacity (Qm = 334.92 mg g−1).•Adsorption mechanism of CYCS/CNC includes chemical and electrostatic adsorption.•The adsorption performance is good even after four regeneration cycles.
Nanodrug delivery systems (NDSs), such as mesoporous silica, have been widely studied because of their high specific surface area, high loading rate, and easy modification; however, they are not ...easily metabolized and excreted by the human body and may be potentially harmful. Hence, we aimed to examine the synergistic anti-tumor effects of ex vivo chemo-photothermal therapy to develop a rational and highly biocompatible treatment protocol for tumors. We constructed a biodegradable NDS using organic mesoporous silica with a tetrasulfide bond structure, copper sulfide core, and folic acid-modified surface (CuS@DMONs-FA-DOX-PEG) to target a tumor site, dissociate, and release the drug. The degradation ability, photothermal conversion ability, hemocompatibility, and in vitro and in vivo anti-tumor effects of the CuS@DMONs-FA-DOX-PEG nanoparticles were evaluated. Our findings revealed that the nanoparticles encapsulated in copper sulfide exhibited significant photothermal activity and optimal photothermal conversion rate. Further, the drug was accurately delivered and released into the target tumor cells, annihilating them. This study demonstrated the successful preparation, safety, and synergistic anti-tumor effects of chemo-photothermal therapeutic nanomaterials.
As a typical metal–organic framework material, UiO-66 has good potential for removing pharmaceuticals and personal care products from water. However, the application of this powdery adsorbent has ...been limited by the difficult recovery from the liquid. To overcome this weakness, we prepared composite beads constituted by sodium alginate and UiO-66 by solidification in CaCl
2
solution. The material was characterized by SEM, FTIR, XRD, BET, and TGA methods. These composite beads were applied to remove a common antibiotic Levofloxacin (LOFX) from water, and the experimental parameters (i.e., initial LOFX concentration, adsorption time, pH, and adsorbent dose) were optimized. The adsorption data could be satisfactorily fitted to the Langmuir isotherm model (
R
2
= 0.9871) and the pseudo-second-order kinetic model (
R
2
= 0.9990). The regeneration experiment of the composite beads revealed that the adsorption efficiency of levofloxacin was higher than 70% even after 5 cycles.
Scheme 1 Synthesis route of UiO-66/CA
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•Novel composite based on polyacrylic acid and magnetic chitosan was carried out.•Magnetic composite shows an efficient removal ratio for Pb(II) .•Magnetic composite remove Pb(II) ...efficiently.•Magnetic composite is well tolerated under acidic conditions.
A creative combination of chitosan with polyacrylic acid (PAA) improves the acidity resistance of chitosan and increases its potential in the field of adsorption. In order to facilitate recovery, magnetic nanoparticles were incorporated in CS–PAA to obtain a magnetic-CS–PAA (MCS–PAA) nanocomposite. The physical and chemical characteristics of the composite adsorbent MCS–PAA were determined by SEM, TEM, FTIR, EDX, XRD, and XPS. This environmental-friendly, magnetic, composite adsorbent showed significantly better adsorption performance than those of the individual adsorbents alone. The maximal adsorption capacity was 204.89 mg/g according to the Langmuir isotherm model, when the concentration of Pb(II) was 100 mg/L at the equilibrium time of 70 min. The main adsorption mechanism was the complexation between the carboxyl, amino, and hydroxyl groups in MCS–PAA and Pb(II). Further, introduction of PAA also improved the acid resistance of CS. The new adsorbent MCS–PAA is thus expected to facilitate a wider range of applications for chitosan in the adsorption of Pb(II).
•M-CCNs@MIP was prepared and well-characterized for FQs adsorption.•M-CCNs@MIP possessed good adsorption properties and reusability.•M-CCNs@MIP exhibited satisfying selective adsorption and ...separation ability for seven FQs form water.
A novel adsorbent with high selectivity for fluoroquinolone (FQ) compounds was developed, based on the surface functionalization of magnetic carboxylated cellulose nanocrystals (M-CCNs) with molecularly imprinted polymer (MIP) comprising amine moieties. The imprinting was achieved by a radical polymerization technique, which uses glycidyl methacrylate, tetraethylenepentamine, ofloxacin, ethylene glycol dimethacrylate, and azobisisobutyronitrile as the functional monomer, active groups provider, template molecule, crosslinking agent, and initiator, respectively. The developed material (M-CCNs@MIP) was comprehensively characterized and shown to exhibit high adsorption capacity and selectivity with rapid equilibration time. Moreover, the adsorption isotherms could be well-fitted with the Freundlich model, and the adsorption kinetics followed the pseudo-second-order model. The maximum adsorption capacities for M-CCNs@MIP after 2 and 20min were 34.09 and 40.65mgg−1, respectively, compared to 9.98 and 15.28mgg−1 observed for the unimprinted polymer (M-CCNs@NIP). By coupling the M-CCNs@MIP adsorbent with high-performance liquid chromatography, an approach was established to enhance the selective adsorption of seven structurally similar FQ compounds in river water samples. The recoveries of the seven FQs ranged from 81.2 to 93.7%, and the limits of detection were between 5.4 and 12.0ngmL−1. The M-CCNs@MIP adsorbent also retained good performance after seven consecutive cycles of reuse.
A novel adsorbent based on the surface of magnetic graphene oxide-grafted cellulose nanocrystal molecularly imprinted polymers (Mag@GO-g-CNCs@MIPs) was developed for the selective extraction and fast ...adsorption of fluoroquinolones (FQs) from river water samples. Cellulose nanocrystals (CNCs) were grafted onto activated graphene oxide (GO), and the surfaces of the obtained magnetic GO-g-CNC particles were molecularly imprinted with polymers using ofloxacin (OFX) as a template molecule and methacrylic acid (MAA) as a functional monomer. The resulting Mag@GO-g-CNCs@MIP material was characterized by Fourier transform infrared spectroscopy, transmission electron microscopy, scanning electron microscopy, vibrating sample magnetometry, and X-ray photoelectron spectroscopy. Under optimum adsorption conditions, the Mag@GO-g-CNCs@MIPs with large specific surface area were easily collected and separated using an external magnetic field. Mag@GO-g-CNCs@MIPs exhibited an ultra-fast adsorption profile for FQs (5 min to achieve the maximum adsorption capacity of 74 mg/g), with imprinting factor values ranging from 1.5 to 3.1. High recognition selectivity towards nine FQs from real river water samples was established through coupling with high-performance liquid chromatography (HPLC), and the recovery of samples spiked with nine FQs was found to be in the range of 79.2–96.1%, with a detection limit ranging from 6.5 to 51 ng/g. Moreover, the data obtained adhered to the Freundlich isotherm model, and the adsorption kinetics followed a pseudo-second-order model. Finally, the Mag@GO-g-CNCs@MIPs could be regenerated and reused for seven consecutive cycles with only a 13% drop in adsorption capacity, indicating its effective application as a new, reusable, and selective adsorbent for the enrichment and separation of FQs from aqueous solutions.
Based on the excellent performances of nanocrystalline cellulose, sodium alginate, or K-carrageenan in Pb
2+
adsorption, nanocrystalline cellulose/sodium alginate/K-carrageenan composite hydrogel ...beads were prepared to adsorb Pb(II) from aqueous solutions. The objective of this study was to demonstrate the excellent potential of the composite hydrogel beads for heavy metal ion adsorption. We successfully prepared ecofriendly Fe-modified nanocrystalline cellulose/sodium alginate/K-carrageenan composite hydrogel beads and characterized them. The structure and adsorption mechanism were investigated using scanning electron microscopy, Fourier-transform infrared spectroscopy, and X-ray photoelectron spectroscopy, and the optimal adsorption conditions were determined. The tricomponent hydrogel beads were robust and exhibited improved adsorption capacity for Pb
2+
and good reusability. The adsorption results could be fitted well with a pseudo-second-order kinetic model and the Langmuir adsorption model. The maximum adsorption capacity obtained by fitting was 351.04 mg g
−1
. Recycling experiments revealed that the adsorption capacity of the adsorbent remained high after five cycles of reuse.
Metal–organic frameworks (MOFs) have received special attention from scientists owing to their excellent adsorption performance. However, the difficulty in separating MOFs from adsorbed metals ...following use has limited their application. A zeolitic imidazole-based MOF with broad applicability for sorption of Pb(II) is examined. In this work, a novel adsorbent employing ZIF-8/calcium alginate microparticles was prepared using sodium alginate and ZIF-8. This adsorbent was characterized using scanning electron microscopy, Fourier-transform infrared spectroscopy, X-ray diffraction analysis, and X-ray photoelectron spectroscopy. The performance of the ZIF-8@CA microparticles in adsorbing Pb(II) from a Pb(II) solution was investigated, and the impacts of the initial Pb(II) concentration, reaction time, pH, and reaction temperature on the reaction process were investigated. The results showed that ZIF-8@CA microparticles exhibited a maximum adsorption capacity of 1321.21 mg/g at pH 5 after 120 min, and the adsorption process was found to fit the Langmuir isotherm model (R 2 = 0.9856) and the pseudo-second-order kinetic model (R 2 = 0.9999). These results showed that the adsorption of Pb(II) was an endothermic process. The regeneration experiment with ZIF-8@CA revealed that the removal efficiency of Pb(II) was greater than 80% even after five cycles.
