Sol-gel Transition Process Research Articles

Nonswellable Hydrogel Patch with Tissue-Mimetic Mechanical Characteristics Remodeling In Vivo Microenvironment for Effective Adhesion Prevention.

Postoperative adhesion is a common complication after abdominal surgery, but current clinical products have unsatisfactory therapeutic effects. Here, we present a hydrogel patch formed in a single step through dialysis. The exchange of DMSO into water facilitates hydrophobic aggregate in situ formation and the formation of hydrogen bonds within the hydrogel. Thanks to the optimized component ratio and precise structural design. The hydrogel patch has soft-tissue-like mechanical characteristics, including high strength, high toughness, low modulus similar to the abdominal wall, good fatigue resistance, and fast self-recovery properties. The nonswellable hydrogel patch retains over 80% of its original mechanical properties after 7 days of immersion in physiological saline, with a maximum swelling ratio of 5.6%. Moreover, the hydrophobic biomultifunctionality of benzyl isothiocyanate can self-assemble onto the hydrogel patch during the sol-gel transition process, enabling it to remodel the inflammatory microenvironment through synergistic antibacterial, antioxidant, and anti-inflammatory effects. The hydrogel patch prevents postsurgical adhesion in a rat sidewall defect-cecum abrasion model and outperforms the leading commercial Interceed. It holds promising potential for clinical translation, considering that FDA-approved raw materials (PVA and gelatin) form the backbone of this effective hydrogel patch.

Correlating 3D printing performance with sol-gel transition based on thermo-responsive k-carrageenan affected by fructose

Thermo-responsive food inks occupy an important part of 3D food printing materials. A great challenge of their accurate 3D printing is to ensure sol-gel transition is adapted to 3D printing process. In this study, k -carrageenan (KG) incorporated with fructose (0–30%, w/v) was selected as a representation of thermo-responsive inks, and their interactive mechanism was investigated. Sol-gel transition and rheology were correlated with 3D printing process in terms of extrusion stage, formation stage, and self-supporting stage. Results indicated that fructose addition increased ink's gelation temperature (Tg) and affected printing temperature selection. During extrusion stage, ink in sol-state with a low viscosity was desirable to enable proper extrudability. While, during formation stage, sol-gel transition speed (gelation time) was important for extruded ink to solidify to avoid continuous spreading. Increased elastic modulus (G′) with fructose addition was beneficial for printed structures to be self-supportable during self-supporting stage. Low field nuclear magnetic resonance (LF-NMR) indicated that water mobility was increasingly restricted with addition of fructose. Hydrogen bond, hydrophobic and electrostatic interactions all significantly affected the KG/fructose ink. Scanning electron microscopy (SEM) suggested that fructose addition resulted in a denser network structure. This study would provide insights on 3D printing of thermo-responsive food inks by correlating with sol-gel transition. • 3D printing behavior was correlated with sol-gel transition process. • 3D printing was divided into three stages and correlated with rheology change. • Fructose addition increased Tg, gelation speed and resultant 3D printing behavior.

Thermally-modulated shape transition at the interface of soft gel filament and hydrophobic substrate

A liquid filament may pinch off into different shapes on interacting with a soft surface, as modulated by the interplay of inertial, capillary, and viscous forces. While similar shape transitions may intuitively be realized for more complex materials such as soft gel filaments as well, their intricate controllability towards deriving precise and stable morphological features remains challenging, as attributed to the complexities stemming from the underlying interfacial interactions over the relevant length and time scales during the sol–gel transition process. Circumventing these deficits in the reported literature, here we report a new means of precisely-controlled fabrication of gel microbeads via exploiting thermally-modulated instabilities of a soft filament atop a hydrophobic substrate. Our experiments reveal that abrupt morphological transitions of the gel material set in at a threshold temperature, resulting in spontaneous capillary thinning and filament breakup. We show that this phenomenon may be precisely modulated by an alteration in the hydration state of the gel material that may be preferentially dictated by its intrinsic glycerol content. Our results demonstrate that the consequent morphological transitions give rise to topologically-selective microbeads as an exclusive signature of the interfacial interactions of the gel material with the deformable hydrophobic interface underneath. Thus, intricate control may be imposed on the spatio-temporal evolution of the deforming gel, facilitating the inception of highly ordered structures of specific shapes and dimensionalities on demand. This is likely to advance the strategies of long shelf-life analytical biomaterial encapsulations via realizing one-step physical immobilization of bio-analytes on the bead surfaces as a new route to controlled materials processing, without demanding any resourced microfabrication facility or delicate consumable materials.

Smart Hydrogels Bearing Transient Gel–Sol–Gel Transition Behavior Driven by a Biocompatible Chemical Fuel

Chemically fueled smart supramolecular gels have been of great interest because of their unique time-dependent properties. However, the vast majority of the already developed examples undergo fueled sol–gel–sol transition, where the gel materials possess nonlinear properties and usually involve the use of toxic chemical fuels, remarkably impeding their real-life applications. Here, we report on supramolecular hydrogels that show dynamic gel–sol–gel transition behavior driven by the consumption of biocompatible cyclodextrin (CD). The addition of CD converts the static hydrogels into sols, which are capable of returning to the original gel states through the spontaneous enzymatic hydrolysis of CD. The gel–sol–gel transition process is highly dynamic and tunable. Importantly, the system resides in a stable gel state after the depletion of the fuel, which would be beneficial for its functions. As an application, the hydrogel is used as a conceptual smart adhesive for fuel-controlled adhesion of model tissues. This work may contribute to the development of biocompatible non-equilibrium materials for high-tech applications, especially in the field of biomedicine.

Nanoscale Kevlar Liquid Crystal Aerogel Fibers.

Aerogel fibers, the simultaneous embodiment of aerogel porous network and fiber slender geometry, have shown critical advantages over natural and synthetic fibers in thermal insulation. However, how to control the building block orientation degree of the resulting aerogel fibers during the dynamic sol–gel transition process to expand their functions for emerging applications is a great challenge. Herein, nanoscale Kevlar liquid crystal (NKLC) aerogel fibers with different building block orientation degrees have been fabricated from Kevlar nanofibers via liquid crystal spinning, dynamic sol–gel transition, freeze-drying, and cold plasma hydrophobilization in sequence. The resulting NKLC aerogel fibers demonstrate extremely high mechanical strength (41.0 MPa), excellent thermal insulation (0.037 W·m–1·K–1), and self-cleaning performance (with a water contact angle of 154°). The superhydrophobic NKLC aerogel fibers can cyclically transform between aerogel and gel states, while gel fibers involving different building block orientation degrees display distinguishable brightness under polarized light. Based on these performances, digital textiles woven or embroidered with high- and low-orientated NKLC aerogel fibers enable up to 6.0 Gb information encryption in one square meter and on-demand decryption. Therefore, it can be envisioned that the tuning of the building blocks’ orientation degree will be an appropriate strategy to endow performance to the liquid crystal aerogel fibers for potential applications beyond thermal insulation.

The dual effects of non-solvent on the sol-gel transition of polyacrylonitrile solution: The promotion in thermodynamics and hindrance in kinetics

The effects of non-solvent on the sol-gel transition of polyacrylonitrile (PAN) solution were investigated in thermodynamics and kinetics by the means of rheology method. The facilitating effects of non-solvent in thermodynamics was illustrated by the variety of viscoelasticity and gel transition temperature (Tgel). With the addition of non-solvent, the mobility of PAN molecular chains are limited due to its increased entanglement. As a result, the PAN solution with higher non-solvent content has lower conformation entropy to satisfy the occurrence of sol-gel transition at higher temperature. It means that less thermodynamic driving is demanded. The kinetical characteristics of PAN solution with different non-solvent content in sol-gel transition process were also discussed. The kinetic hindrance of non-solvent was proved by the gradually stronger time-dependence of loss tangent with the addition of non-solvent during sol-gel transition. This apparent extending of relaxation time is resulted from the more restriction of the mobility of PAN molecules. The gelation activation energy (Egel) was calculated according to Ozawa method. The results also indicated that the activity of PAN molecules in this transition became weaken with the addition of non-solvent since a relative tight connection between PAN molecules was there. Therefore, the formation of physical junction points for sol-gel transition was hindered due to the decreasing of the mobility of self-adjustment for PAN molecules. This is the fundamental reason for the kinetic hindrance role of non-solvent.

Localized delivery of curcumin by thermosensitive hydrogels for promoting wound healing.

Curcumin can promote wound healing, but its drug delivery medium needs to be improved further. A curcumin-loaded thermosensitive hydrogel was prepared, its characterization was evaluated, and its promoting effect on wound healing was observed. Curcumin-loaded thermosensitive hydrogels were prepared with different percentages of poloxamer 188 and poloxamer 407. A small tube inversion assay was used to observe the sol-gel transition temperature, and a rotational rheometer was used to detect the sol viscosity, sol-gel phase transition temperature, and phase transition time. The microstructure of the gel was observed by scanning electron microscopy, and Fourier infrared spectroscopy was used to evaluate whether curcumin was successfully loaded. Finally, its promoting effect on wound healing was observed in vivo and in vitro. Poloxamer 407 24% and poloxamer 188 1% were selected to prepare curcumin-loaded thermosensitive hydrogels. After 60±15s at 32°C, the sol-gel transition process was completed, with certain elastic behavior and solid-like rheological properties. Scanning electron microscopy showed that the pores of the curcumin-P407/P188 thermosensitive hydrogel were interconnected, with an average pore size ranging from 5 to 10μm. Hydrogels showed a higher swelling ratio. Fourier transform infrared spectroscopy showed that curcumin had been incorporated into the hydrogel. Live/dead cell assays suggested that the hydrogel was not toxic to fibroblasts. Curcumin-loaded thermosensitive hydrogels can promote an increase in S-phase fibroblasts and improve wound healing. Curcumin-loaded P407/P188 thermosensitive hydrogel improves wound healing. More in-depth research is needed in the future.

Injectable and biodegradable double-network nanocomposite hydrogel with regulable sol-gel transition process and mechanical properties

Alginate hydrogels have the most extensively explored injection system among natural molecular. The injectable alginate hydrogel has special physical and biological properties without toxicity, therefore, it has been served as minimally invasive treatments to treat various irregular defects. However, the inconvenient truth is low formability and poor mechanical properties of injectable alginate hydrogels; besides, there are little relevant studies about controlling, measurement and analysis of the sol-gel transition and degradation process. We synthesized an injectable nanocomposite alginate hydrogel, used specific methods and equipment to regulate and evaluate the sol-gel transition of the hydrogel, moreover, we researched the degradation behaviour using scanning electron microscope, nano-indenter and titration analysis. The results showed that gelation time and mechanical properties could be regulated and effectively described. Compression properties of the hydrogels increased to 150%–300% compared with common alginate hydrogels, in addition, the degradation behaviour with ions release could be regulated by the formula. The results will be propitious to solve problems in quality control of hydrogel manufacturing engineering and the nanocomposite hydrogels with good biocompatibility will have great potential for multifunctional biological scaffolds and tissue engineering.

Chitin derived nitrogen-doped porous carbons with ultrahigh specific surface area and tailored hierarchical porosity for high performance supercapacitors

In this study, we report the fabrication of nitrogen rich activated nanosized carbon with hierarchical micro/mesoporous and ultrahigh specific surface area by template-free and one-step carbonization-activation method, which greatly simplified the process and avoided the waste of reagents. Chitin nanoparticles were prepared by a mechanical induced sol-gel transition process in NaOH/Urea solvent and a subsequent carbonization utilizing NaOH for activation and urea for N doping, resulting in activated carbon (ACNC-800) with extraordinary specific surface area (2631 m2/g) and high nitrogen content (7.1%). Further characterization and electrochemical tests demonstrate high electrochemical performance of the activated nanocarbon. Under the current density of 0.5 A/g, the specific capacitance of the three-electrode system is 245 F/g and that of the two-electrode system is 227 F/g. The assembled capacitors exhibit superior rate performance and good cycle stability (98% capacitance retention after 10000 charge-discharge cycles). This work introduces a simple and efficient strategy to prepare N-doped carbon with hierarchical porosity applied to high performance supercapacitors.

Photo‐curing 3D printing robust elastomers with ultralow viscosity resin

AbstractPhotosensitive resins with ultralow viscosity suitable for the silicone‐based elastomers by 3D printing were reported. Based on the facile one‐pot strategy which involved photo‐polymerization of hydroxyethyl acrylate (HEA) and sol–gel transition process of methyltrimethoxysilane (MTMS), silicone‐based elastomers with tunable mechanical properties could be obtained by adjusting the ratio of HEA and MTMS as needed. Due to the physically cross‐linked network formed by hydrogen bonds between hydroxyl group of polyhydroxypropyl acrylate (PHEA) and the chemically cross‐linked network formed by MTMS, the stress and strain of printed elastomers reached 3.75 MPa and 205% respectively demonstrating its performance has reached the average level of already reported photo‐curable elastomers. The photosensitive resins with high curing rate and low viscosity are suitable for 3D printing technique.

Comparative study between cold and hot water extracted polysaccharides from Plantago ovata seed husk by using rheological methods

Cold and hot water extracted polysaccharides (CP and HP) were isolated from Plantago ovata seed husk at 25 and 85 °C, respectively. Their rheological properties were systematically investigated and compared. Different concentrations and temperatures were studied to evaluate the viscoelastic properties of the two fractions. It was found that CP solutions behaved as viscous fluids, while HP solutions preferred to exhibit as gel-like structure. The sol-gel transition process of HP was evaluated and the gel point was determined to be 4.8 mg/mL by Winter-Chambon method in water at 25 °C. The steady flow sweep investigated the viscosity properties of CP solutions and two critical concentrations were found, which locating the transition from the dilute to semi-dilute region, and from the semi-dilute to concentrated region. In addition, the two fractions could form thermo-reversible weak gels, and the gelation temperatures of them increased with the increase of concentration. It is evident that both polysaccharides have significant potential for application in food industry.

Surface wettability and emission behavior tuned via solvent in a supramolecular self-assembly system based on a naphthalene diimides derivative

A new gelator (1) based on a naphthalene diimide derivative with two adamantane groups was designed and synthesized, to form stable organogels in 1,4-dioxane, DMSO, ethyl acetate, THF/H2O (1/1, v/v), acetone, toluene, methanol and ethanol under the driving force of noncovalent bonding. Gel 1 in toluene exhibited thixotropic properties. The gel could change to a sol by mechanical force, and recover in 5 s. The sol-gel transition process of gel 1 was thoroughly investigated via field emission scanning electron microscopy (FESEM), ultraviolet visible spectra (UV–vis), fluorescence (FL), X-ray powder diffraction (XRD), Fourier Transform Infrared Spectroscop (FTIR) and contact angles (CA). The emission properties and xerogel surface wettability properties could be modulated via the solvent. The supra-hydrophobic surface with the contact angle of 146° was obtained from gel 1 in DMSO and exhibited the characteristic of “lotus-effect”. The hydrophobicity of film 1 produced profound effects on the fluorescence intensity and the lifetime of the excited state. This work offers a new way to construct supra-hydrophobicity via self-assembly.

A highly efficient thermo responsive palladium nanoparticles incorporated guar gum hydrogel for effective catalytic reactions

Hydrogel, especially stimuli responsive hydrogel, has attracted enormous attention due to its unique properties for many applications. Herein, Pd NPs@ CNCs was firstly attained by in situgeneration of Pd NPs onto CNCs, and subsequently incorporated into guar gum-based hydrogel, so that a thermo responsive Pd NPs@ CNCs/ guar gum hydrogel catalytic system was obtained. The sol-gel transition was achieved viaa simple heating/cooling cycle: a sol state was obtained above 70 °C, allowing the catalytic reaction; a gel state was attained below 20 °C, allowing the reuse/ recycling of the Pd NPs. Pd NPs were formed by in situ reduction of PdCl2 in the presence of CNCs so that Pd NPs were loaded onto CNCs surfaces. CNCs acted as stabilizers for the Pd NPs. The TEM image showed that the average size of Pd NPs is ˜3 nm. Subsequently, the Pd NPs@ CNCs composites were loaded into the guar gum hydrogel, based on the boron crosslinking chemistry. The hydrogel exhibited rapid sol-gel transition process upon heating (70 °C) and cooling (20 °C) cycles. The Pd NPs loaded sol-gel transition concept was subsequently applied to the Suzuki coupling reactions between aryl bromides and phenyl boronic acids, and a highly efficient catalytic performance (over 85% yield within 2 h) was obtained. The reuse/recycling of the thermo responsive Pd NPs@ CNCs/guar gum hydrogel catalyst system was investigated. This novel Pd NPs loaded thermo-responsive sol-gel transition concept is a promising new catalytic system.

Preparation and properties of a temperature- and pH- responsive polypeptide hydrogel

Stimuli-responsive polypeptide hydrogel has attracted a great deal of interests because of the biodegradability, biocompatibility and the response-ability to external stimuli. Here we synthesized triblock copolymers methoxy-poly (ethylene glycols)-b-poly (L-lysine)-b-poly (L-valine) (mPEG-PLysx-PVy) by sequential ring opening polymerization. Through adjusting the length of hydrophilic and hydrophobic segments, we constructed a temperature- and pH- responsive hydrogel system using polymer mPEG-PLys2-PV7. The phase diagram from test tube inversion method showed that the gel transition temperature could cover the body temperature (37 °C) and decreased with the elevated pH value. TEM and FTIR measurements proved that the secondary structure of the polymer solution was mainly β–sheet structure, and the sol-gel transition process was caused by both the dehydration of mPEG and the change of the secondary structure. After loading DOX in hydrogels, we investigated the drug release behavior in vitro at different pH values. The results showed that the drug release at pH5.5 was faster than that at pH 7.4. About 36% and 100% of loaded drug was respectively released from hydrogels at 37 °C within 48 h at pH 7.4 and pH 5.7. This polypeptide hydrogel material might be used as drug targeting release system and does not affect normal tissues due to its significant pH sensitivity.

Regulation of gel formation, hierarchical structures, rheological behavior, and surface wettability via the linker of molecule center on bis(cholesteric) derivatives supramolecular self-assembly systems

A series of novel gelators (1–3) based on bis(cholesteric) derivatives with different molecular centers were designed and characterized. Their differences in molecule structures were only the linkers of molecule center. Their self-assembly process were carefully studied through different techniques including field emission scanning electron microscope (FESEM), UV–vis absorption spectra, fourier transform infrared (FTIR) spectra, rheology, X-ray diffraction (XRD) and water contact angles. Hydrophobic interaction and weak hydrogen bonding interaction may be the main driving force for gel formation. More significant, the gelation ability, self-assembly process, rheological behavior, and surface wettability of these self-assembly systems could be adjusted via the linker of molecule center. With the flexibility of the linker increasing, the gelation ability was gradually decreased. Different self-assembly structures from microrods to nanofibers were obtained in the sol-gel transition process of compounds 1–3. J-type aggregation mode was employed in gel systems 2 and 3. Interestingly, the mechanical strength of gel systems 2 and 3 was obviously stronger than that of gel system 1 in the same solvent. Xerogel film of 2 with the “lotus effect” exhibited more hydrophobicity with contact angle of 148.5° than that of xerogel films of 1 and 3. This work will bring a new method for tuning supramolecular self-assembly through the linker of molecule center.

Chitosan/cellulose sulfate mesoporus microspheres for the adsorptive removal of pollutants from water

The discharge of effluents is steadily increasing, resulting in serious damages to the environment. Considerable attentions have been paid to magnetic bioadsorbent technology to solve these environmental problems because of their low cost and high efficiency. A thermally induced sol-gel transition process in ionic liquid was conducted to produce microspheres from chitosan and cellulose sulfate in order to develop a novel bioasorbant. The developed adsorbents were characterized using Fourier transform infrared (FT-IR) spectra, scanning electron microscopy (SEM), and an Energy Dispersive Spectrometer (EDS). The adsorption performance was evaluated with a simulated waste water containing Congo red and heavy metals. Results indicated that the synthesized CHT-CS-Fe3O4 microspheres exhibited mesoporous property and a good sphericity with an approximate diameter of 20 µm. The composite microsphere showed an excellent performance in removing the anion dye Congo red with removal efficiency of 68% and adsorbing divalent lead with the maximum adsorption capacity qm of 189 mg/g as well as removal efficiency of 93%. The material exhibited a highly selective property for the adsorption of different metals from the solution. These properties suggest that CHT-CS-Fe3O4 microspheres have the potential for application in water treatment.

Injectable temperature-sensitive hydrogel with VEGF loaded microspheres for vascularization and bone regeneration of femoral head necrosis

The formation of neovascularization inside the bone scaffold could enhance and accelerate the regeneration of large bone defects in femoral head necrosis, the angiogenic growth factors are predominantly expressed during the early phase for a reestablishment of the vascularity. In this paper, the injectable temperature-sensitive star-shaped poly(D,L-lactic-co-glycolic acid)-b-methoxy poly(ethylene glycol) (PLGA-mPEG) block copolymer was developed, during the sol-gel transition process, the vascular endothelial growth factor (VEGF) loaded linear PLGA-mPEG block copolymer microspheres and vascular endothelial cells (VECs) were composited into to form hydrogels. The release of VEGF from hydrogel was delayed compared to that from microspheres. The fluorescent imaging confirmed that VECs had a good proliferation into the hydrogels. The hydrogels were injected into necrosis site of the femoral head, the vessels were observed for 2 weeks, the vessels density and mean vessels diameters increased in next 4–6 weeks, followed by increasing new bone formation. These results suggested that injectable VEGF loaded microspheres/hydrogels composites could be applied for vascularization and bone regeneration of femoral head necrosis.

The Application of Small-Angle Light Scattering for Rheo-Optical Characterization of Chitosan Colloidal Solutions.

In the recent studies on chitosan hydrogels, it was found that understanding both rheological and structural properties plays an important role in their application. Therefore, a combination of two independent techniques was applied to investigate micro- and macroscopic properties of chitosan colloidal system. Studies on viscous properties, as well as the sol-gel phase transition process, were performed using rheological methods coupled with the small angle light scattering (SALS) technique. Based on the anisotropy of scattering patterns obtained during rotational shear tests, it was found that the chitosan solution reveals two different behaviors delimited by the critical value of the shear rate. Below a critical value, chitosan clusters are deformed without breaking up aggregates, whereas after exceeding a critical value, chitosan clusters apart from deformation also breakup into smaller aggregates. The values of the radius of gyration determined by applying the Debye function allow one to state that with an increase of chitosan concentration, molecule size decreases. An analysis of the light scattering data from the temperature ramp test showed that with an increase of temperature, the level of polymer coil swelling increases. Simultaneously, the supply of thermal energy leads to a neutralization of the charge of chitosan chains. As a consequence, the formation of intermolecular links occurs and a gel structure is formed.

Hyaluronic acid in Pluronic F-127/F-108 hydrogels for postoperative pain in arthroplasties: Influence on physico-chemical properties and structural requirements for sustained drug-release

In this study, we reported the hyaluronic acid (HA) on supramolecular structure of Pluronic F-127 (PLF-127) and/or Pluronic F-108 (PLF-127) hydrogels, as well as their effects on release mechanisms, looking forward their application as lidocaine (LDC) drug-delivery systems in arthroplastic surgeries. We have studied the HA-micelle interaction using Dynamic Light Scattering (DLS), the micellization and sol-gel transition processes by Differential Scanning Calorimetry (DSC) and Rheology., of PL-based hydrogels and. The presence of HA provided the formation of larger micellar dimensions from ~26.0 to 42.4nm. The incorporation of HA did not change the micellization temperatures and stabilized hydrogels rheological properties (G′>G″), showing no interference on PL-thermoreversible properties. Small-Angle-X-ray Scattering (SAXS) patterns revealed that HA incorporation effects were pronounced for PLF-127 and PLF-108 systems, showing transitions from lamellar to hexagonal phase organization (HA-PLF-127) and structural changes from cubic to gyroid and/or cubic to lamellar. The HA insertion effects were also observed on drug release profiles, since lower LDC release constants (Krel=0.24–0.41mM·h−1) were observed for HA-PLF-127, that presented a hexagonal phase organization. Furthermore, the HA-PL systems presented reduced in vitro cytotoxic effects, pointed out their tendency to self-assembly and possible application as drug delivery systems.

Improved Solid-Phase Synthesis of Phosphorylated Cellulose Microsphere Adsorbents for Highly Effective Pb2+ Removal from Water: Batch and Fixed-Bed Column Performance and Adsorption Mechanism

A highly effective adsorbent with phosphate groups bound to cellulose microspheres was designed by an improved solid-phase modification method to adsorb lead ions from water by a batch and fixed-bed column method. The phosphorylated cellulose microsphere adsorbents were prepared through esterification by which phosphate groups were introduced to the interface of regenerated cellulose microspheres which were previously prepared through a sol–gel transition process from a simple cellulose solution. Their morphological, structural, and physicochemical properties were characterized by SEM, FTIR, XRD, and DSC, etc. Furthermore, EDX and XPS were used to confirm the chemical modification process and to investigate their phosphate adsorption mechanism. In the batch adsorption experiments, the equilibrium time and adsorption capacity were determined by both equilibrium and kinetic adsorption experiments, which were also conducted to investigate the adsorption mechanism. In the dynamic adsorption experiments, multi...