Effect of nitric acid oxidation on the surface of hydrochars to sorb methylene blue: An adsorption mechanism comparison

Abstract

The capacity and underlying mechanism of hydrochars derived from commercial D-glucose and wasted orange peels (designated as pristine-hydrochars) and further modified with nitric acid (designated as oxidized-hydrochars) to adsorb methylene blue were investigated. Both pristineand oxidized-hydrochars were characterized by scanning electron microscopy, Brunauer-Emmet-Teller-specific surface area, Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, and mass titration. The maximum methylene blue adsorption capacity at 30 C

Adsorption process of naproxen onto peanut shell‐derived biosorbent: important role of n–π interaction and van der Waals force

“…In addition, an increase in the solution temperature caused a significant decrease in the amount of naproxen adsorbed by PS, suggesting that the process of naproxen removal might be exothermic in nature and mainly involve physical adsorption. In general, the adsorption process involved in the weak force (i.e., van der Waals) often tends to release adsorbates adsorbed on the surface of adsorbent into the solution when temperatures increase (also known as a desorption phenomenon) 35,36 . In other words, van der Waals force played a key role in the adsorption process of naproxen onto the biosorbent.…”

“…3(a)) after adsorption might confirm the existence of such interaction. However, the π-π interaction mechanism often has a less important contribution to adsorb organic compounds onto the adsorbent exhibiting weak aromatic structure (biosorbent 35 and hydrochar 26,36 ) when compared to that exhibiting strong aromatic structure (biochar 31 and activated carbon 37 ).…”

Lignoceliuliozinės žematemperatūrės bioanglies hidrofiliškumo didinimo tyrimai ir technologijos kūrimas

“…Šie rezultatai rodo, kad funkcinės grupės bioanglyje nėra pašalinamos po jos fizikinės modifikacijos garais. Kitu tyrimu (Nguyen et al, 2019) Bioanglies porų charakteristikos buvo įvertintos naudojantis azoto adsorbcija. Modifikuotos bioanglies N2 adsorbcijos-desorbcijos izotermės bei porų dydžio pasiskirstymai pavaizduoti 3.29 ir 3.30 paveiksluose.…”

Sugarcane Bagasse-derived Hydrochar: Modification with Cations to Enhance Phosphate Removal

“…Synthesis of hydrochar via hydrothermal carbonization (HTC) has been investigated as an approach for increasing biomass valued-products. Conversion of biomass waste to adsorbent for removal of organic and inorganic contaminants is an environmental aspect that has received considerable attention due to its simplicity and ability to produce hydrochars with attractive characteristics that promote effective use in dealing with pollutant contamination in aqueous solution (Jain et al, 2016;Nguyen et al, 2019). HTC is the thermochemical conversion technique in a closed reactor that uses moderate processing temperature (180-240°C) and water as carbonatization medium under self-generated pressures to react with wet/dry materials and convert the biomass into solid materials, namely hydrochar (Congsomjit and Areeprasert, 2020;Dai et al, 2014).…”

“…HTC is the thermochemical conversion technique in a closed reactor that uses moderate processing temperature (180-240°C) and water as carbonatization medium under self-generated pressures to react with wet/dry materials and convert the biomass into solid materials, namely hydrochar (Congsomjit and Areeprasert, 2020;Dai et al, 2014). HTC process offers significant advantages over pyrolysis, a conventional utilized process for biomass-to-carbon-based products conversion, in terms of mild reaction condition, lower energy consumption process, and the ability to deliver hydrochar with high concentrations of oxygenated functional groups (OFGs, i.e., carboxylic, hydroxyl, and phenolic) on the surface (Jain et al, 2016;Nguyen et al, 2019;Petrović et al, 2016). The relative abundance of OFGs on hydrochar's surface plays an important role in the adsorption capacity of hydrochar toward the given contaminants.…”