Synthesis, characterization, and adsorption properties of collagen and attapulgite‐filled copolymer biocomposites: Batch and column studies

Synthesis, characterization and column adsorption properties of gum ghatti and water hyacianth derived cellulose grafted poly(vinyl sulfonic acid-co-acrylamide) composites

Vinylsulfonic acid (VSA), acrylamide (AM) and N, N methylene bis acrylamide(MBA) were copolymerized by radical polymerization in the presence of gum ghatti (GG) and treated water hyacianth (WH) in water. Several composite copolymers were prepared by varying the i) AM: VSA molar ratios ii) wt% of GG and iii) wt% of treated WH based on a Box-Behnken Design(BBD) of a response surface methodology (RSM) model with three input variables and the batch adsorption capacity (mg/g) of 100 mg/L Cd (II) from water as response. The composite polymer was characterized by Fourier transform Infrared spectroscopy (FTIR), X-ray diffraction (XRD), thermogravimetric analysis(TGA), X- ray photo electron spectroscopy (XPS), compressive strength, pH reversibility, pH at point zero charge (pHPZC), Brunauer-Emmett-Teller (BET) surface area and scanning electron microscopy (SEM). The network parameters of the composites were determined. The copolymer composite prepared with AM: VSA of 5:1 containing 10 wt% GG and 4 wt% treated WH showed an optimum batch adsorption capacity of 399.15 mg/g Cd (II) from water containing 100 mg/L Cd (II). The same composite showed an adsorption capacity of 170.1 mg/g and a removal% of 31.5 at a feed concentration/feed flow rate/bed height of 150 mgL-1/30mLmin-1/30 mm in a fixed bed column.

Design of advanced separators for high performance Li-S batteries using natural minerals with 1D to 3D microstructures

Lithium-sulfur (Li-S) batteries are of great interest due to their high energy density. However, polysulfides shuttle and low S loading severely impede their practical applications. Here, we report design of advanced separators for Li-S batteries using natural minerals with 1D to 3D microstructures. Four natural minerals with different microstructures including 1D halloysite nanotubes, 1D attapulgite nanorods, 2D Li⁺-montmorillonite (Mmt) nanosheets and 3D porous diatomite were used together with carbon black (CB) for preparation of the mineral/CB-Celgard separators. The Si-OH groups of the minerals act as Lewis acid sites, which could effectively absorb polysulfides by forming LiO and OS bonds with polysulfides. Among all the separators, the Mmt/CB-Celgard separator endowed the Li-S battery with the highest upper plateau discharge capacity (369 mA h g^-1), initial reversible capacity (1496 mA h g^-1 at 0.1 C), rate performance and cycling stability (666 mA h g^-1 after 500 cycles at 1.0 C with 0.046% capacity decay per cycle). The Mmt/CB-Celgard separator also enabled stable cycling of the Li-S battery with high S loading (8.3 mg cm^-2) cathode. This work will provide inspiration for future development of advanced separators for high-energy-density Li-S batteries.