Hydrogels with diffusion-facilitated porous network for improved adsorption performance

Advances in structure designing and function tailoring strategy toward alginate-based hydrogels for efficient water remediation: A review

Alginate (mainly sodium alginate, SA), as a natural polysaccharide material, has been widely applied in water remediation due to its excellent biocompatibility, degradability, and high hydration properties. Alginate hydrogels exhibit high adsorption capacity, effectively removing heavy metal ions, dyes, antibiotics, phosphate ions, and other pollutants from wastewater. This review begins with a description of the chemical structure of sodium alginate and its physicochemical properties, followed by a detailed discussion of the preparation methods of alginate-based composite hydrogels, including physical and chemical crosslinking, emulsification, electrostatic complexation, self-assembly, ultrasound and microwave-assisted methods. Based on the different compositions of the composites, alginate-based composite hydrogels are classified into several types for the removal of specific pollutants. Moreover, the paper systematically summarizes the research progress of alginate-based composite hydrogels in adsorbing heavy metal ions, dyes, antibiotics, phosphate ions for application effects. Although alginate-based composite hydrogels demonstrate great potential in water remediation, challenges such as insufficient mechanical strength, poor regeneration ability, and low stability under extreme conditions still exist. Finally, the future development prospects of alginate composite hydrogels in the field of water remediation, as well as potential research directions to improve their adsorption performance, enhance their regeneration capacity, and improve their environmental friendliness are presented.

Adsorptive Effect of Corn Silk-Loaded Nickel Oxide and Copper Oxide Nanoparticles for Elimination of Ciprofloxacin from Wastewater

Ciprofloxacin (CIP) is one of the most reported antibiotic pollutants in hospital and industrial wastewater systems. The inclusion of nanosized transition metal oxides in adsorbent materials is able to improve the affinity and aqueous phase uptake of CIP from water. In this study, we report for the first time composites of corn silk with impregnated nanoparticles of NiO (NiONPs-CS) and CuO (CuONPs-CS) for the removal of CIP from water. The adsorbent was characterized using scanning electron microscopy (SEM), Fourier transform infrared (FTIR), energy-dispersive X-ray spectroscopy (EDX), an adsorption/desorption analyzer, and X-ray diffractometer (XRD) to study the morphology, surface functionality, elemental composition, textural properties, and crystal phases. The monolayer adsorption capacities of NiONPs-CS and CuONPs-CS were 108.3 and 120.2 mg/g, which were over 2 times higher than the capacity for unloaded corn silk. The kinetics of the adsorptive uptake followed the pseudo-second-order kinetics, revealing that both adsorption site density and CIP aqueous concentration control the removal rate. NiONPs-CS and CuONPs-CS were reusable for five cycles, with the uptake efficiency being 63.1 and 66.9%, respectively. This dropped to 47.8% for the unloaded corn silk. The mechanism of uptake was mainly by electrostatic attraction, pi-pi interaction, hydrogen bonding, and hydrophobic interaction. Based on our findings, the adsorbents have proven to be an efficient, cheap, and reusable material for CIP uptake.

Efficient Elimination of Inorganic/Organic Pollutants by Fe3O4/biochar@sodium Alginate Gel Beads

The magnetic composite gel bead (Fe3O4-C@SA GB) adsorbent was prepared by sodium alginate (SA) crosslinking with pitaya peel-derived porous carbons (PPDPCs) and magnetic iron oxide nanoparticles (Fe3O4 NPs). The adsorption effects of Fe3O4-C@SA GBs on heavy metal ions (HMIs) and 17 β-estradiol (E2) in water are evaluated by classical kinetic models and isotherm models. The pseudo-second-order kinetic model shows that Fe3O4-C@SA GBs have maximum adsorption capacities of 9.62, 7.50, and 13.61 mg/g for Cu (II), Cd (II), and Pb (II), respectively. Meanwhile, the highest adsorption performance of the synthesized gel beads to E2 is of ca. 276.3 mg/g. In addition, the Fe3O4-C@SA GBs can still maintain a high level of adsorption efficiency after five adsorption cycles, displaying economic efficiency and reusability. Hence, this work provides useful insights into the efficient adsorption elimination of pollutants in sewage and the corresponding adsorption mechanisms.

Nanofiber Hydrogel Drug Delivery System for Prevention of Postsurgical Intestinal Adhesion

Intestinal adhesion is one of the complications that occurs more frequently after abdominal surgery. Postsurgical intestinal adhesion (PIA) can lead to a series of health problems, including abdominal pain, intestinal obstruction, and female infertility. Currently, hydrogels and nanofibrous films as barriers are often used for preventing PIA formation; however, these kinds of materials have their intrinsic disadvantages. Herein, we developed a dual-structure drug delivery patch consisting of poly lactic-co-glycolic acid (PLGA) nanofibers and a chitosan hydrogel (NHP). PLGA nanofibers loaded with deferoxamine mesylate (DFO) were incorporated into the hydrogel; meanwhile, the hydrogel was loaded with anti-inflammatory drug dexamethasone (DXMS). The rapid degradation of the hydrogel facilitated the release of DXMS at the acute inflammatory stage of the early injury and provided effective anti-inflammatory effects for wound sites. Moreover, PLGA composite nanofibers could provide sustained and stable release of DFO for promoting the peritoneal repair by the angiogenesis effects of DFO. The in vivo results indicated that NHP can effectively prevent PIA formation by restraining inflammation and vascularization, promoting peritoneal repair. Therefore, we believe that our NHP has a great potential application in inhibition of PIA.

Hydrogel Applicability for the Industrial Effluent Treatment: A Systematic Review and Bibliometric Analysis

In recent decades, hydrogels, as adsorption materials, have received important attention due to their characteristics and properties, such as mechanical strength, biocompatibility, biodegradability, swellability, and stimuli sensitivity. In the actual framework of sustainable development, it has been imperative to develop practical studies of hydrogels in the treatment of actual industrial effluents. Accordingly, the current work has, as its objective, to make evident hydrogels' applicability in the treatment of actual industrial effluents. For this purpose, a bibliometric analysis and systematic review based on the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) method were conducted. The relevant articles were selected from the Scopus and Web of Science databases. Some important findings were that: (1) China is the leading country when it comes to hydrogel application in actual industrial effluents, (2) the motor studies are focalized on the treatment of wastewater by hydrogels, (3) the fixed-bed columns are suitable unit equipment for the treatment of industrial effluents of using hydrogels, and (4) the hydrogels show excellent adsorption capacities of ion and dye contaminants present in industrial effluents. In summary, since the implementation of sustainable development in 2015, the progress of practical hydrogel applications in the treatment of industrial effluent has been receiving more attention, and the selected studies demonstrate the implementation viability of these materials.

New insight into continuous recirculation-process for treating arsenate using bacterial biosorbent

In this study, a new recirculation column reactor system for arsenate removal using a polyethylenimine coated bacterial biosorbent was developed. Solution pH was the most important factor in process design and operation. In order to control and optimize solution pH favorable for arsenate removal, a pH control and recirculation system was added to a column reactor. The effects of recycle ratio, initial arsenate concentration, and flow rate on the arsenate removal performance of the developed process were examined. Thomas and Yoon-Nelson models were used to interpret the breakthrough curve of arsenate removal. The maximum arsenate adsorption amount of the new reactor was determined to be 50.86 mg/g by the Thomas model. Importantly, the new reactor showed unimpeded adsorption performance compared with that in the batch experiments. The desorption study also showed excellent reusability. The results indicated that the newly developed process could be a promising application prospect for removing arsenate.

Biomaterials to Prevent Post-Operative Adhesion

Surgery is performed to treat various diseases. During the process, the surgical site is healed through self-healing after surgery. Post-operative or tissue adhesion caused by unnecessary contact with the surgical site occurs during the normal healing process. In addition, it has been frequently found in patients who have undergone surgery, and severe adhesion can cause chronic pain and various complications. Therefore, anti-adhesion barriers have been developed using multiple biomaterials to prevent post-operative adhesion. Typically, anti-adhesion barriers are manufactured and sold in numerous forms, such as gels, solutions, and films, but there are no products that can completely prevent post-operative adhesion. These products are generally applied over the surgical site to physically block adhesion to other sites (organs). Many studies have recently been conducted to increase the anti-adhesion effects through various strategies. This article reviews recent research trends in anti-adhesion barriers.

Materials engineering, processing, and device application of hydrogel nanocomposites

Hydrogels are widely implemented as key materials in various biomedical applications owing to their soft, flexible, hydrophilic, and quasi-solid nature. Recently, however, new material properties over those of bare hydrogels have been sought for novel applications. Accordingly, hydrogel nanocomposites, i.e., hydrogels converged with nanomaterials, have been proposed for the functional transformation of conventional hydrogels. The incorporation of suitable nanomaterials into the hydrogel matrix allows the hydrogel nanocomposite to exhibit multi-functionality in addition to the biocompatible feature of the original hydrogel. Therefore, various hydrogel composites with nanomaterials, including nanoparticles, nanowires, and nanosheets, have been developed for diverse purposes, such as catalysis, environmental purification, bio-imaging, sensing, and controlled drug delivery. Furthermore, novel technologies for the patterning of such hydrogel nanocomposites into desired shapes have been developed. The combination of such material engineering and processing technologies has enabled the hydrogel nanocomposite to become a key soft component of electronic, electrochemical, and biomedical devices. We herein review the recent research trend in the field of hydrogel nanocomposites, particularly focusing on materials engineering, processing, and device applications. Furthermore, the conclusions are presented with the scope of future research outlook, which also includes the current technical limitations.

A visually distinguishable light interfering bioresponsive silica nanoparticle hydrogel sensor fabricated through the molecular imprinting technique

Methods of the early detection of diseases are based on recognition of the smallest change in the levels of a disease-specific biomarker in body fluids.