One-pot synthesis of brewer's spent grain-supported superabsorbent polymer for highly efficient uranium adsorption from wastewater

Advances in the valorization of brewing by-products

Beer is the most consumed alcoholic beverage worldwide, and its production involves the generation of a huge volume of by-products (i.e., spent grain, spent hop, and spent yeast). This review aims to highlight the main properties of these by-products as a valuable source of biomolecules (i.e., proteins, cellulose, hemicellulose, lignin, phenolic compounds, and lipids) and the biorefining methods used in the last decade for their valorization. The pros and cons of the technologies employed will be shown, highlighting which of them could be more ready for the transition to an industrial scale, and which applications (e.g., food and feed, bioenergy, biochemicals, and biomaterials) are the most feasible.

A review: Examining the effects of modern extraction techniques on functional and structural properties of cellulose and hemicellulose in Brewer's Spent Grain dietary fiber

Brewer's Spent Grain (BSG) is a by-product of the brewing industry, rich in dietary fibers that offer various health benefits. This review delves into the molecular and structural transformations of BSG and dietary fibers (arabinoxylan, beta-glucan, cellulose etc.) extracted from BSG, triggered by recent advancements in extraction technologies. Through an analysis of current methodologies, such as advanced solubilization methods and emerging technologies like ultrasonication, this paper discusses their significant improvement in yield of BSG-dietary fiber and impact on the structural and functional properties of BSG-dietary fibers (BSG-DF). The review highlights how these technologies enhance fiber solubilization and modify physicochemical properties, thereby improving their functionality in food applications. Furthermore, the review aims to bridge gaps in current research and suggest future directions for optimizing extraction processes to better exploit these fibers in the food industries.

Simple synthesis of graphene oxide-supported and phosphorylated chitosan gel bead to uptake uranium from wastewater

With the development of the nuclear industry, the direct discharge of uranium-containing wastewater has become increasingly harmful to the environment. A novel graphene oxide-supported and phosphoric-crosslinked chitosan gel bead (C-PGCB) with excellent uranium uptake capability was successfully fabricated to treat uranium-containing wastewater. The experimental results showed that the introduction of PO and CO bonds through phosphoric acid crosslinking could greatly improve the capturing ability of chitosan-based materials, which could reach 97.1 % and 460.9 mg g-1 within 20 min, respectively. In the presence of multiple coexisting ions, the adsorbent still maintained high uranium adsorption efficiency. After 5 cycles, the uptake efficiency of C-PGCB with good cycle stability remained above 90 %. The fitting both the dynamic model and the isotherm model showed that the uranium uptake of C-PGCB was a uniform single-layer chemisorption process. Furthermore, the excellent dynamic separation properties proved the great potential value in the uranium-containing wastewater treatment. The uptake of C-PGCB for uranium could be owed to synergistic complexation and electrostatic interaction between uranium and multifunctional groups on C-PGCB. This work offered a chitosan-based adsorbent to effectively remove uranium from wastewater and gave a novel and effective way for the construction of chitosan-based adsorbents to enhance capture performance.

One-step synthesis of phospho-rich, silica-enhanced chitosan aerogel for the efficient adsorption of uranium(VI)

In this study, an amorphous silica reinforced, phosphoric-crosslinked chitosan foam (P-CTS@SixOy) was prepared. The introduction of amorphous silica not only increased the affinity of the adsorbent for uranium, but also improved the stability of the material. The number of active sites of P-CTS@SixOy was increased by the introduction of phosphate groups. The material exhibited excellent uranium adsorption performance with the removal capacity and efficiency of 850.5 mg g-1 and 98.1 %, respectively. After regenerations, the morphology of P-CTS@SixOy still maintained, and the uranium adsorption efficiency remained above 90 %, manifesting the excellent cycle performance of P-CTS@SixOy. In the dynamic adsorption experiment, P-CTS@SixOy successfully concentrated the volume of uranium-containing solution, and exhibited excellent uranium adsorption performance. The analysis of kinetics, isotherms, and thermodynamics manifested that the uranium adsorption behavior of P-CTS@SixOy was a spontaneous, endothermic, monolayer chemical adsorption process. X-ray photoelectron spectroscopy, Scanning Electron Microscope, and Fourier Transform Infrared Spectrometer were used to characterized the P-CTS@SixOy before and after adsorption, which demonstrated that the main interaction mechanism between uranium and P-CTS@SixOy was the complexation. These studies indicated the huge application prospect of P-CTS@SixOy in the treatment of large-scale uranium-containing wastewater.

An approach of pectin from Citrus aurantium L. for superabsorbent resin with superior quality for hygiene products: Salt resistance, antibacterial, nonirritant and biodegradability

In this paper, a kind of superabsorbent resin (SAR) with superior quality for hygiene products was developed using Fructus Aurantii Immaturus pectin (FAIP) from Citrus aurantium L.. FAIP-g-AM/AMPS SAR was established by free radical graft co-polymerization with FAIP as skeleton structure, N, N'-Methylene-bis (acrylamide) (MBA) as the cross-linker. Meanwhile, the functional monomers of acrylamide (AM) and 2-acrylamido-2-methylpropane sulfonic acid (AMPS) were introduced. The structure and morphology of FAIP-g-AM/AMPS were characterized by FTIR, ¹³C NMR, XRD, SEM and TG-DSC analysis. The results confirmed that the AFIP-g-AM/AMPS SAR was successfully prepared, which exhibited a three-dimensional (3D) network structure and an excellent thermal stability. The absorption and retention capacity of FAIP-g-AM/AMPS was comparable to or even better than commercial diapers and sanitary napkins. Significantly, FAIP-g-AM/AMPS itself exhibited excellent antibacterial and safety. FAIP-g-AM/AMPS has an inhibition ratio of 97.1 % for Escherichia coli (E. coli) and 98.5 % for Staphylococcus aureus (S. aureus), and was non-irritating and non-allergic to the skin. In addition, FAIP-g-AM/AMPS presented amazing biodegradability and a weight loss reached 37.1 % after 30 days by soil burial test. The research provides a safe and high-performance SAR, which expected to be used in hygiene products such as baby diapers, adult incontinence pads and sanitary napkins.

Appreciatively Efficient Sorption Achievement to U(VI) from the El Sela Area by ZrO2/Chitosan

The need to get uranium out of leaching liquid is pushing scientists to come up with new sorbents. This study uses the wet technique to improve the U(VI) sorption properties of ZrO2/chitosan composite sorbent. To validate the synthesis of ZrO2/CS composite with Zirconyl-OH, -NH, and -NH2 for U(VI) binding, XRD, FTIR, SEM, EDX, and BET are used to describe the ZrO2/chitosan wholly formed. To get El Sela leaching liquid, it used 150 g/L H2SO4, 1:4 S:L ratio, 200 rpm agitation speed, four hours of leaching period, and particle size 149–100 µm. In a batch study, the sorption parameters are evaluated at pH 3.5, 50 min of sorbing time, 50 mL of leaching liquid (200 mg/L U(VI)), and 25 °C. The sorption capability is 175 mg/g. Reusing ZrO2/CS for seven cycles with a slight drop in performance is highly efficient, with U(VI) desorption using 0.8 M acid and 75 min of desorption time. The selective U(VI) recovery from El Sela leachate was made possible using ZrO2/CS. Sodium diuranate was precipitated and yielded a yellow cake with a purity level of 94.88%.