Cross-linked chitosan microspheres entrapping silver chloride via the improved emulsion technology for iodide ion adsorption

Fluorescent cellulose nanofibrils-based hydrogel incorporating MIL-125-NH2 for effective adsorption and detection of iodide ion

To remove iodine ion (I-) from wastewater, a novel hydrogel, the fluorescent cellulose nanofibrils-based hydrogel (FCNH), was synthesized to enable both detection and adsorption of I-. The FCNH comprised cellulose nanofibrils (CNs), silver nanoclusters (AgNCs), and MIL-125-NH2. It exhibited an excellent adsorption capacity for I-, with a maximum adsorption capacity of 373.7 mg/g, fitting both the Langmuir and pseudo-second-order models. Additionally, FCNH displayed excellent regeneration properties, retaining 88.0 % of its initial adsorption capacity after six adsorption-desorption cycles. Functioning as a fluorescent sensor, the synthesized FCNH enabled the detection of I- through dynamic quenching, with linear ranges of 5 to 200 mg/L and 0.2 to 1.0 μg/L, and a determination limit of 0.11 μg/L. Analysis of the adsorption and detection mechanisms revealed that FCNH's outstanding performance arose from its 3D porous structure comprising CNs, AgNCs, and MIL-125-NH2. Economic analysis indicated that FCNH was inexpensive compared to commercially available activated carbon. Thus, FCNH demonstrated significant potential as an economical and reusable adsorbent for iodine ion removal.

MIL-88A(Al)/chitosan/graphene oxide composite aerogel with hierarchical porosity for enhanced radioactive iodine adsorption

To ensure the sustainable development of the nuclear industry, the effective capture of radioiodine from nuclear wastewater has attracted much attention. Herein, a novel MIL-88A(Al)/chitosan/graphene oxide (MCG) composite aerogel was prepared by using crosslinked chitosan and graphene oxide as the 3D network skeleton, and MIL-88A(Al) nanocrystalline particles were introduced into the skeleton by freeze-drying method. MIL-88A(Al) adsorption capacities for volatile and soluble iodine were 2.02 g g-1 and 850.00 mg g-1, respectively. Owing to the synergistic effect of MIL-88A(Al), GO, CS, and the hierarchically porous structures of the MCG aerogel, the adsorption capacities for volatile and soluble iodine by the MCG aerogel were increased to 2.62 g g-1 and 1072.60 mg g-1, respectively. Furthermore, the adsorption performance of the MCG aerogel for volatile and soluble iodine could be maintained at 83 % and 82 % after 5 cycles, suggesting excellent recoverability. Meanwhile, the adsorption mechanism studies showed the interactions between iodine and NH, AlO, and CO in MCG aerogel. Furthermore, the adsorption process is consistent with the Elovich kinetic and Sips isotherm models. MCG aerogels are potential candidates for enhanced radioiodine adsorption due to their high radioiodine capture performance and excellent recyclability.

Preparation and modification of polymer microspheres, application in wastewater treatment: A review

The removal of various pollutants from water is necessary due to the increasing requirements for the removal of various pollutants from wastewater and the quality of drinking water. Polymer microspheres are regarded as exemplary adsorbent materials due to their high adsorption efficiency, excellent adsorption performance, and ease of handling. Herein, the advantages and disadvantages of different preparation methods, modifications, applications and the current research status of polymer microspheres are summarized at large. Furthermore, the enhanced performance of modified composite microspheres is emphasized, including adsorption efficiency, thermal stability, and significant improvements in physical and chemical properties. Subsequently, the current applications and potential of polymeric microspheres for wastewater treatment, including the removal of inorganic and organic pollutants, heavy metal ions, and other contaminants are summarized. Finally, future research directions for polymer microspheres are proposed, outlining the challenges and solutions associated with the application of polymer microspheres in wastewater treatment.

Cu/Al2O3 aerogels for high-efficiency and rapid iodide elimination from water

Cu-based functional materials are excellent candidates for the elimination of iodine anions. However, the low utilization rate of Cu and its unsatisfactory adsorption performance limit its large-scale practical applications. This paper proposes a co-gelation method to obtain Cu/Al₂O₃ aerogels with a high specific area (537 m²/g). Cu/Al₂O₃ aerogels have a hierarchical porous structure and contain a high proportion of Cu (20.5 wt%). The high dispersibility of Cu, which is based on an in-situ gel process, provides conditions for the high-efficiency elimination of iodide anions. We conducted adsorption experiments that demonstrated that the fabricated Cu/Al₂O₃ aerogel had an ultrahigh adsorption capacity (407.6 mg/g) and a fast adsorption equilibrium time (0.5 h) for iodide anions. Additionally, the Cu/Al₂O₃ aerogel could selectively capture iodine anions even in the presence of high concentrations of competing ions (NO₃^-, SO₄^2-, and Cl^- at 60 mmol/L). Importantly, the aerogel can operate in a wide pH range of 3-11 without causing secondary pollution. This work demonstrates that low-cost Cu/Al₂O₃ aerogels exhibit great potential for eliminating radioactive iodine anions.

Functional microspheres for tissue regeneration

As a new type of injectable biomaterials, functional microspheres have attracted increasing attention in tissue regeneration because they possess some advantageous properties compared to other biomaterials, including hydrogels. A variety of bio-inspired microspheres with unique structures and properties have been developed as cellular carriers and drug delivery vehicles in recent years. In this review, we provide a comprehensive summary of the progress of functional and biodegradable microspheres that have been used for tissue regeneration over the last two decades. First, we briefly introduce the biomaterials and general methods for microsphere fabrication. Next, we focus on the newly developed technologies for preparing functional microspheres, including macroporous microspheres, nanofibrous microspheres, hollow microspheres, core-shell structured microspheres, and surface-modified functional microspheres. After that, we discuss the application of functional microspheres for tissue regeneration, specifically for bone, cartilage, dental, neural, cardiac, and skin tissue regeneration. Last, we present our perspectives and future directions of functional microspheres as injectable carriers for the future advancement of tissue regeneration.

Magnetic chitosan microspheres: An efficient and recyclable adsorbent for the removal of iodide from simulated nuclear wastewater

The efficient and recyclable magnetic chitosan microspheres (MCMs) were successfully synthesized to remove iodide from nuclear wastewater and characterized through XRD, FTIR, SEM, EDS, VSM, TGA and XPS. The characterization results indicated that the MCMs exhibited smooth spherical morphology and good magnetic properties. The removal potential of MCMs was investigated for iodide (I^-) anions at different conditions. From pH 3 to pH 9, MCMs performed the high I^- removal efficiency (>90%). The maximum I^- removal capacity of MCMs was up to 0.8087 mmol g^-1 at 298 K, well-fitting with the pseudo-second-order and Sips models. Furthermore, the I^- removal efficiency of MCMs still maintained more than 91% after five adsorption-desorption cycles, performing good regeneration and reusability. This study is expected to prompt the MCMs to become an efficient and recyclable biosorbent for iodide removal from nuclear wastewater.

The hollow core-shell ferric oxide entrapped chitosan microcapsules as phosphate binders for phosphorus removal in vitro

Patients in hyperphosphatemia are orally prescribed with phosphate binders to excrete the non-metabolic phosphorus. Aiming for the bio-compatibility and binding efficacy, the Fe-based phosphate binders of low toxicity have been explored and improved. Herein, the hollow core-shell microcapsules as Fe@CH (nano ferric oxide entrapped in the polymerized chitosan) were constructed via emulsion interface polymerization, to enhance the phosphate binding from -NH₂ group and iron complex, and limit iron leakage significantly. Via the double emulsion polymerization based on the primary Pickering emulsion stabilized by oleic acid-modified ferric oxide, Fe@CH performed as the rough polymerized-chitosan microcapsules entrapping well-distributed ferric oxide for the phosphate adsorption in vitro. At pH 3 and pH 5, Fe@CH bound phosphorus efficiently, with the capacity of 55 mg/g and 65 mg/g respectively, along with the excellent shell isolation from iron leakage and remarkable safety. Prospectively, the Fe@CH micro-sorbent is the proper candidate as the phosphate binder for hyperphosphatemia.

Polymeric Iodophors: Preparation, Properties, and Biomedical Applications

The review summarizes the data on the main chemical and physiological properties of iodine and its capability of complexation with natural and synthetic polymers. Iodine is the best known antiseptic used to prevent and treat microbial infections. Its unique capability of complexation with certain polymers opens wide opportunities for targeted and prolonged delivery to target organs. Polymeric complexes with iodine have another color, other morphology, a higher electrical conductivity, and higher biological activity as compared with initial polymers. The formation of and ions is associated with iodine-polymer complexation. Iodine-containing biocompatible adhesive controlled-release formulations are designed as part of research into iodine-polymer complexes. The field is promising in terms of treating certain diseases because tolerance to iodine compounds does not usually develop in microbial cells.

Network interior and surface engineering of alginate-based beads using sorption affinity component for enhanced phosphate capture

In order to alleviate the environmental problems caused by excessive discharge of phosphate, an environmental friendly and highly efficient bio-sorbent (SA-La@PEI) for phosphate was fabricated by combing strategies of sorption affinity component mediated and poly(ethylenimine) surface engineering of alginate beads. Various characterization methods like SEM, FTIR, XRD and XPS were adopted to examine the morphology and functional group composition of SA-La@PEI. Through detailed tests, SA-La@PEI exhibited excellent adsorption performance of 121.2 mg/g, which was better than most published materials. More importantly, the outstanding phosphate selectivity of SA-La@PEI was exposed when NO₃^-, HCO₃^-, SO₄^2- and Cl^- were added to the phosphate solution. Considering the integrated components in composites, both chemical precipitation and electrostatic attraction can be considered as the dominant mechanisms of phosphate adsorption. Totally, as-prepared SA-La@PEI beads might be a promising sorbent for the decontamination of excessive phosphate because of its low-cost, excellent adsorption performance and mechanical strength.