Rice husk hydrochars from metal chloride-assisted hydrothermal carbonization as biosorbents of organics from aqueous solution

Abstract

Hydrochar a carbon-rich material resulting from hydrothermal carbonization of biomass, has received substantial attention because of its potential application in various areas such as carbon sequestration, bioenergy production and environmental amelioration. A series of hydrochars were prepared by metal chloride-assisted hydrothermal carbonization of rice husk and characterized by elemental analysis, zeta potential, X-ray diffraction, Brunauer–Emmett–Teller measurements, Fourier transform infrared spectroscopy, thermogravimetric analysis, X-ray photoelectron spectroscopy and scanning electron microscopy. The results reveal that the prepared hydrochars have carbon contents ranging from 45.01 to 58.71%, BET specific areas between 13.23 and 45.97 m2/g, and rich O-containing functional groups on the surfaces. The metal chlorides added in the feedwater could improve the degree of carbonization and show significant effects on the physical, chemical and adsorption properties of the hydrochars. The adsorption of the selected organics on the hydrochars is a spontaneous and physisorption-dominated process. The hydrochars possess larger adsorption capacities for 2-naphthol than for berberine hydrochloride and Congo red, and the modeling maximum adsorption capacities of 2-naphthol are in the range of 170.1–2680 mg/g. The adsorption equilibrium could be accomplished in 10, 40 and 30 min for 2-naphthol, berberine hydrochloride and Congo red, respectively. These results suggest metal chloride-assisted hydrothermal carbonization a promising method for converting biomass waste into effective adsorbents for wastewater treatment.

Cross-Interaction of Fish Scales and Poplar-Derived Bio-oil Enhance Pore Development via Carbonization and Activation

“…Figure g,h displays the distribution of functional groups on the surface of feedstock and the activated carbons. The stretching vibrations of −OH (∼3690–3275 cm –1 ), C–H (∼3035 cm –1 ), −CH 2 (∼2924 cm –1 ), CC (∼1546 cm –1 ), CO (∼1660 cm –1 ), C–O–C (∼1039–1150 cm –1 ), and Ar–H (∼865–466 cm –1 ) were observed . FS contained prominent absorption of CO, which arose from the stretching vibration of amide I band of collagen, while absorption of C–N and…”

Synthesis and Characterization of Hydrochar and Bio-oil from Hydrothermal Carbonization of Sargassum sp. using Choline Chloride (ChCl) Catalyst

“…It acts as an expansive agent, infiltrating the biomass framework to create large pores, but its dehydrating effects and ability to limit tar formation are less than ZnCl2 (Peng et al, 2016). This phenomenon explains that CaCl2, in general, has a lower hydrochar yield than ZnCl2 (Li et al, 2021).…”

Rapid Waste Motor Oil Conversion into Diesel-Range Hydrocarbons Using Hydrochar as Catalyst: Kinetic Study and Product Characterization

“…FTIR spectra show typical peaks for rice husk after carbonization. Functional groups such as O-H (3400 and 1625 cm −1 ), C=H (between 2850 and 3000 cm −1 ), C=O (around 1710 cm −1 ), and C=C (around 1625 cm −1 ) [26][27][28] are observed, which become more intense at higher carbonization temperatures and after treatment. Moreover, typical for rice husks, a peak between 1100 and 1000 cm −1 corresponds to Si-O-Si, following the high silica content of rice husks.…”