Compatibility study of nanofiltration and reverse osmosis membranes with 1-cyclohexylpiperidenium bicarbonate solutions

Life Cycle Assessment of Innovative Carbon Dioxide Selective Membranes from Low Carbon Emission Sources: A Comparative Study

Carbon capture has been an important topic of the twenty-first century because of the elevating carbon dioxide (CO₂) levels in the atmosphere. CO₂ in the atmosphere is above 420 parts per million (ppm) as of 2022, 70 ppm higher than 50 years ago. Carbon capture research and development has mostly been centered around higher concentration flue gas streams. For example, flue gas streams from steel and cement industries have been largely ignored due to lower associated CO₂ concentrations and higher capture and processing costs. Capture technologies such as solvent-based, adsorption-based, cryogenic distillation, and pressure-swing adsorption are under research, but many suffer from higher costs and life cycle impacts. Membrane-based capture processes are considered cost-effective and environmentally friendly alternatives. Over the past three decades, our research group at Idaho National Laboratory has led the development of several polyphosphazene polymer chemistries and has demonstrated their selectivity for CO₂ over nitrogen (N₂). Poly[bis((2-methoxyethoxy)ethoxy)phosphazene] (MEEP) has shown the highest selectivity. A comprehensive life cycle assessment (LCA) was performed to determine the life cycle feasibility of the MEEP polymer material compared to other CO₂-selective membranes and separation processes. The MEEP-based membrane processes emit at least 42% less equivalent CO₂ than Pebax-based membrane processes. Similarly, MEEP-based membrane processes produce 34-72% less CO₂ than conventional separation processes. In all studied categories, MEEP-based membranes report lower emissions than Pebax-based membranes and conventional separation processes.

An easy and unique design strategy for insoluble humic acid/cellulose nanocomposite beads with highly enhanced adsorption performance of low concentration ciprofloxacin in water

In this work, two plant wastes were reused to fabricate the homogeneous 3D micro-nano porous structured humic acid/cellulose nanocomposite beads (IHA@CB) embedded with insoluble humic acid (IHA) particles. The subtle synthesis method attributed to the homogenous distribution of IHA particles in the cellulose matrix and improved the adsorption performance of IHA@CB for low concentration ciprofloxacin in water. Physical and chemical properties of the beads were characterized by SEM, EDX, XRD, FTIR, and the adsorption process of ciprofloxacin was studied by isotherm, kinetic and dynamic adsorption experiments. The maximum adsorption capacity of IHA@CB on CPX reached 10.87 mg g^-1 under 318 K. The dynamic experiments were conducted by adjusting bed height, flow rate, initial concentration and pH values, and the regeneration experiments proved the adsorbent exhibited good repeatability. The adsorption mechanism was revealed that CPX was adsorbed by IHA@CB mainly through cation exchange.

Treatment of furazolidone contaminated water using banana pseudostem biochar engineered with facile synthesized magnetic nanocomposites

The present study enlightens facile synthesis and characterization of magnetic biochar derived from waste banana pseudostem biomass for the removal of nitrofuran antibiotic 'furazolidone' (FZD). Brunauer-Emmett-Teller (BET), scanning electron microscopy (SEM), magnetic hysteresis, X-ray diffraction (XRD), and Fourier transform infrared spectroscopy (FTIR) revealed successful hybridization of magnetic nanocomposites with biochar (BPB₆₀₀). The maximum adsorption capacity of magnetic BPB₆₀₀ was 96.81% (37.86 mg g^-1), which was significantly higher than the non-coated BPB₆₀₀ (77.25%; 31.45 mg g^-1). Adsorption kinetics data fitted well with pseudo-second order, and Elovich model demonstrating dominance of the chemisorption mechanism. Furthermore, the response surface methodology (RSM) was applied to evaluate the interactive effect of pH, temperature, and FZD concentration on adsorption. Therefore, the results of present study would provide an effective strategy to tackle antibiotic contaminants responsible for the antibiotic resistance genes or bacteria that decreases the therapeutic value of antibiotics.

Synthetic draw solutes for forward osmosis: status and future

Forward osmosis (FO) has developed rapidly over the past decade. The development of draw solutes, a key component of FO processes, has also progressed remarkably. A wide range of synthetic draw solutes have been explored in recent years. Synthetic draw solutes exhibit superiority over the conventional draw solutes obtained commercially in terms of lower reverse solute fluxes and less energy consumption in draw solute recycling. However, there are still some big challenges for synthetic draw solutes, such as complicated synthetic procedures, low water fluxes, severe concentration polarization (CP) and decreased water recovery efficiency when recycled draw solutes are reused in FO. These challenges are also the current research focus on the exploration of novel draw solutes. This article aims to review the recent progress especially on synthetic draw solutes. Their design strategies, synthesis routes and FO performance are assessed. Some representative applications involving the synthetic draw solutes-facilitated FO processes are exemplified. The advantages and disadvantages of the existing synthetic draw solutions are evaluated. The challenges and future directions in exploring novel draw solutes are highlighted.