High performance and sustainable CNF membrane via facile in-situ envelopment of hydrochar for water treatment.

In this study, cellulose nanofiber (CNF) membranes for water treatment are prepared via in-situ hydrothermal carbonization of glucose in a CNF suspension. The in-situ carbonized CNFs were fabricated into the membranes via dead-end filtration under hydraulic pressure (1 bar). The in-situ carbonized CNF membranes showed high pure water flux (56.25 L·h-1·m-2) without critical flux drop for 12 h of membrane fabrication. The hydrochar chemically bonded with CNF enhanced the durability of CNF during membrane fabrication. Owing to the strong and stable electrostatic interaction between the target dye and hydrochar, the in-situ carbonized membrane also displayed excellent dye rejection for dilute and concentrated solutions, with high selectivity and good reusability. This study provides a successful strategy for fabricating an all-carbohydrate-based high-performance water treatment membrane.

Carbon dot/cellulose nanofiber composite: Dataset for its water treatment performance.

Carbon dot (CD) obtained via one-step hydrothermal carbonization was attached to cellulose nanofiber (CNF) via physical blending and in-situ synthesis. The data represent the morphological, chemical and optical differences of the samples, according to the amount and introducing method of CD. The morphological durability of the samples was also shown. The water treatment membrane performance was analysed using methylene blue as a representative pollutant. The related article was published in Carbohydr. Polym. 255 (2021) 117387.

In-situ synthesis of carbon dot at cellulose nanofiber for durable water treatment membrane with high selectivity.

In this work, carbon dot (CD) was in-situ synthesized and attached to cellulose nanofiber (CNF) via hydrothermal process. The in-situ synthesized CD uniformly enveloped the CNF surface by means of amide bonding, without significant changes of the chemical structure of CNF. The prepared CD@CNF composite showed rough and bumpy morphology. The attached CD increased the interaction between the fibers and enhanced the thermal stability and the dimensional stability in aqueous solution. CD@CNF showed excellent performance as a dye-rejection membrane with high-water flux (∼32 LMH bar-1) and high rejection rate (∼99.8 %), as well as the selective removal of cationic dye. This study suggests a novel synthesizing method of durable CNF membrane by envelopment of CD for effective water treatment.

Characterization of food waste-driven carbon dot focusing on chemical structural, electron relaxation behavior and Fe3+ selective sensing.

In the study, carbon dot (CD) with high fluorescence properties was obtained via one-step hydrothermal carbonization of food model and sandwich leftover, respectively. The data in the article represent the change of the chemical structure and PL properties of the food waste-driven carbon dot (FWCDs). In higher carbonization temperature, pyridinic N and graphitic N were increased while amino N and pyrrolic N was decreased. The lifetime was increased with the increase of temperature. The CD prepared from sandwich leftover showed the dependency of the emission on the exciting wavelength and excellent Fe3+ sensitivity without significant change of lifetime. It also had a pH-sensitive fluorescence feature and good stability in NaCl solutions. For more insight, please see Food waste-driven N-doped carbon dots: Applications for Fe3+ sensing and cell imaging Ahn et al., 2019.

Food waste-driven N-doped carbon dots: Applications for Fe3+ sensing and cell imaging.

We report highly fluorescent N-doped carbon dots (CDs) synthesized from food waste via one-step hydrothermal carbonization. To study the chemical transition of carbon dots from food wastes, the cat feed stocks driven from food waste were used as the waste model. In the model study, the core of the CDs was successfully self N-doped without extra pre- or post-treatments. The experimental results reveal that the nitrogen in the waste model played an important role in the formation of graphitic N and pyridinic N in the core and functional groups on the surface. Especially, high process temperature (≥180 °C) resulted in high quantum yield as 23% of the CDs from the waste model. To demonstrate the conversion of real food waste into CDs, the hamburger sandwich leftover was used as a precursor for CDs. The food waste driven CDs had similar chemical and fluorescent properties to that of the waste model, having quantum yield of 28%. This study exhibits the food waste driven carbon dots are excellent candidates for fluorescence probe to Fe3+ with high selectivity even under the interference of other metal, and for bio-imaging material with good cell viability over 80%.