Preparation of Carboxymethyl Cellulose-g- Poly(acrylamide)/Attapulgite Porous Monolith With an Eco-Friendly Pickering-MIPE Template for Ce(III) and Gd(III) Adsorption

Fabrication of porous adsorbents from eco-friendly aqueous foam for high-efficient removal of cationic dyes and sustainable utilization assessment

Porous materials applied in environmental remediation have received researchers' extensive attention recently, but the related green and convenient preparation method is rarely reported. Here, we recommended a green and convenient strategy for the fabrication of porous material via aqueous foam templates, which was synergistically stabilized by Codonopsis pilosula (CP) and clay minerals of attapulgite (APT). The characterization results revealed that the APT was modified by organic molecules leached from CP and anchored at the air-water interface, which improved the foam stability significantly. The novel porous material of polyacrylamide/Codonopsis pilosula/attapulgite (PAM/CP/APT) templated from the aqueous foam via a polymerization reaction had excellent adsorption capacity for the cationic dyes methyl violet (MV) and methylene blue (MB), and the adsorption capacity can reach 755.85 mg/g and 557.64 mg/g, respectively. More importantly, the adsorption capacity of spent adsorbent material was still over 200 mg/g after being recycled five times through a simple carbonization process, and then it was added to the plant pot, the total biomass was increased by about 86.42%. This study provided a green and sustainable pathway for the preparation, application and subsequent processing of porous materials.

Microvesicle-Embedded Solid-liquid Composite Coating for the Tribological Behavior Regulation and Long-Acting Lubrication

Friction interfaces in liquid-embedded composite lubrication coatings commonly comprise a combination of discontinuous fluid films and rough solid contact surfaces, which together ensure easy shearing and a prolonged wear life. However, achieving high efficacy in mixed lubrication poses a challenge due to the conflicting nature of enhanced migration freedom for the liquid lubricant and increased mechanical strength of the solid matrix. Recent efforts have focused on incorporating reinforcing fillers to develop multicomponent, multiphase composites that can address this paradox. Here, we describe a modified attapulgite (APT) with strong biphasic wettability via the oil decompressive osmosis treatment on APT nanocontainers grafted with long nonpolar alkyl chains. This modified APT enables control over the size, distribution, and mobility of lubricant droplets by constructing a Pickering emulsion and toughens the solid-phase matrix through dispersion strengthening. Additionally, the introduction of APT induces the formation of a solid tribofilm during friction, which possesses a higher oil adsorption capacity, as verified through first-principles calculations based on density functional theory (DFT). Consequently, the fluid films can be replenished by the fracture of nanocontainers and adsorption from the bulk phase; further comprehensive and effective regulation of the friction interface leads to low friction and wear.

Ion exchange capacity of synthetic zeolite L: a promising way for cerium recovery

The increasing rare earth elements' (REE) demand to meet the market request and the current political scenario show that it is essential to find good solutions to recover these elements from waste (both industrial and mining). Zeolites are microporous materials with high cation exchange capacity, up to now only little investigated for REE recycle. Here, we propose the use of NH4+-exchanged zeolite L for Ce recovery from a very diluted solution (0.002 M), mimicking the Ce3+ concentration of the liquors deriving from the leaching of spent catalysts. The aim of this work is twofold: (i) to investigate the exploitability of zeolite L as cation exchanger in the Ce recovery; and (ii) to determine the best working conditions. The investigated process consists of a coupled cation exchange: (1) in the first exchange the NH4+ cations - present in the zeolite porosities - are exchanged with the Ce3+ ions in the solution; and (2) in the second experiment, the Ce3+ trapped into the zeolite is recovered through a further exchange with NH4. The best working conditions for Ce3+ exchange of NH4-zeolite L are: batch system, liquid/solid ratio equal to 90 mL/g and 180 mL/g, 24 h of contact at 25 °C. The resulting Ce adsorption capacity (qt) is equal to ~25 mg/g and ~39 mg/g and the removal efficiency 100% and 77% for the two tested liquid/solid ratios, respectively. The kinetics was proved to be fast and consistent with industrial timing; no energy cost for temperature setting is required; and the acid pH (~4) of the solutions does not affect the zeolite structure stability and its exchange performance. It has been demonstrated that the zeolite framework is not affected by the exchange so that the same absorbent material can be employed many times.

Waste Fiber-Based Poly(hydroxamic acid) Ligand for Toxic Metals Removal from Industrial Wastewater

Toxic metals in the industrial wastewaters have been liable for drastic pollution hence a powerful and economical treatment technology is needed for water purification. For this reason, some pure cellulosic materials were derived from waste fiber to obtain an economical adsorbent for wastewater treatment. Conversion of cellulose into grafting materials such as poly(methyl acrylate)-grafted cellulose was performed by free radical grafting process. Consequently, poly(hydroxamic acid) ligand was produced from the grafted cellulose. The intermediate products and poly(hydroxamic acid) ligand were analyzed by FT-IR, FE-SEM, TEM, EDX, and XPS spectroscopy. The adsorption capacity (q_e) of some toxic metals ions by the polymer ligand was found to be excellent, e.g., copper capacity (q_e) was 346.7 mg·g⁻¹ at pH 6. On the other hand, several metal ions such as cobalt chromium and nickel also demonstrated noteworthy sorption capacity at pH 6. The adsorption mechanism obeyed the pseudo second-order rate kinetic model due to the satisfactory correlated experimental sorption values (q_e). Langmuir model isotherm study showed the significant correlation coefficient with all metal ions (R² > 0.99), indicating that the single or monolayer adsorption was the dominant mode on the surface of the adsorbent. This polymer ligand showed good properties on reusability. The result shows that the adsorbent may be recycled for 6 cycles without any dropping of starting sorption capabilities. This polymeric ligand showed outstanding toxic metals removal magnitude, up to 90–99% of toxic metal ions can be removed from industrial wastewater.

Preparation of an ion imprinted chitosan-based porous film with an interpenetrating network structure for efficient selective adsorption of Gd(iii)

In this work, a new Gd(III) ion imprinted CS-based porous film with interpenetrating network structure was fabricated by a simple polymerization–evaporation approach for the efficient selective adsorption of Gd(III) from aqueous solution.

Polymer Ligands Derived from Jute Fiber for Heavy Metal Removal from Electroplating Wastewater

Industrial operations, domestic and agricultural activities worldwide have had major problems with various contaminants caused by environmental pollution. Heavy metal pollution in wastewater also a prominent issue; therefore, a well built and economical treatment technology is demanded for pollution-free wastewater. The present work emphasized pure cellulose extracted from jute fiber and further modification was performed by a free radical grafting reaction, which resulted in poly(methyl acrylate) (PMA)-grafted cellulose and poly(acrylonitrile)-grafted cellulose. Subsequently, poly(hydroxamic acid) and poly(amidoxime) ligands were prepared from the PMA-grafted cellulose and PAN-grafted cellulose, respectively. An adsorption study was performed using the desired ligands with heavy metals such as copper, cobalt, chromium and nickel ions. The binding capacity (qe) with copper ions for poly(hydroxamic acid) is 352 mg g-1 whereas qe for poly(amidoxime) ligand it was exhibited as 310 mg g-1. Other metal ions (chromium, cobalt and nickel) show significance binding properties at pH 6. The Langmuir and Freundlich isotherm study was also performed. The Freundlich isotherm model showed good correlation coefficients for all metal ions, indicating that multiple-layers adsorption was occurred by the polymer ligands. The reusability was evaluated and the adsorbents can be reused for 7 cycles without significant loss of removal performance. Both ligands showed outstanding metals removal capacity from the industrial wastewater as such 98% of copper can be removed from electroplating wastewater and other metals (cobalt, chromium, nickel and lead) can also be removed up to 90%.