A Novel Nitrogen Enriched Hydrochar Adsorbents Derived from Salix Biomass for Cr (VI) Adsorption

Abstract

Hydrochars were prepared from Salix by hydrothermal carbonization, and characterized by FT-IR, 13C NMR, XPS, UV-vis, TG, SEM and BET techniques. The results showed that the hydrochars with molecular sieve-type open pore structure contained numbers of oxygen and nitrogen functional groups, which benefited the adsorption and diffusion of adsorbent Cr (VI). The hydrochar obtained from 26 h reaction (HC-26) was indicated an excellent adsorbent compared to the commercial activated carbon, and its maximum removal efficiency for Cr (VI) reaches up to 99.84% at pH 1. Langmuir´s model is well fitted the experimental equilibrium adsorption data of total Cr. The bath experiment results showed that Cr (VI) could be removed rapidly in the first 300 min. Furthermore, the adsorption kinetics process of HC-26 could be described by pseudo-second-order model. Based on the above results, HC-26 could be acted as a potential efficient adsorbent for removal of Cr (VI) from aqueous solution.

Preparation, characterization and cost analysis of activated biochar and hydrochar derived from agricultural waste: a comparative study

“…The reason for BTS is due to the lignin and cellulose structures of the sample was extremely damaged and/or disappeared during pyrolysis. During the HTC process, the acidic medium has gradually seeped into the amorphous cellulose and some soluble segments of lignin of straw resulting in cracked and disrupt the cellulose chain [2]. Further, it can be seen good dispersion of water molecule into the matrix and the fiber did not agglomerate during hydrolysis resulting in HTS exhibited higher interfacial adhesion and smooth heterogeneous surfaces with dull surface edges.…”

“…The sustainable material research gives a primary concern on two major criteria's, such as rising environmental concerns and the need for cost-effective competitive products. Arguably, the use of biomass as a source of the carbonaceous product has recently become popular due to their availability, feasibility and biodegradable in nature [1,2]. They have a potential to be converted to solid, liquid and gaseous products.…”

“…In this manner, the issues of carbon synthesis under sustainable conditions was as of late returned to and actualized by a few terms, where catalytic treatment of biomass relatively in the mild condition provided bulk, mesoporous or nanostructured chars. Moreover, the suitability of both biochar and hydrochars can be improved through chemical activation via HCl [14], ZnCl 2 [1], H 3 PO 4 [2], KOH [15], etc., since they provide high surface area and high porosity [16]. In this regard, several literature works have reported the performance of various agricultural wastes such as rice husk [17], Perennial grass [18], wheat straw [19], etc.…”

A comparative study on defluoridation capabilities of biosorbents: Isotherm, kinetics, thermodynamics, cost estimation and regeneration study

“…The reason for raw BTS is due to the lignin and cellulose structures of the sample was extremely damaged and/or disappeared during pyrolysis. During the HTC process, the acidic medium has gradually seeped into the amorphous cellulose and some soluble segments of lignin of straw resulting in cracked and disrupts the cellulose chain [21]. The SEM after fluoride adsorption were observed to be a uniform morphological distribution of particles containing scattershot pores and smooth heterogeneous surfaces with dull edges in both adsorbents.…”

“…The presence of such functional groups with its carbonized features on the surface of hydrochar enabled it to be a promising precursor for fluoride treatment. Moreover, the suitability of both biochar and hydrochars can be improved through chemical activation via HCl [19], ZnCl2 [20], H3PO4 [21], KOH [22], etc., since they provide high surface area and high porosity, which are primarily responsible for effective fluoride adsorption [23]. Activation through H3PO4 is, however, most preferable as compared to other activation chemicals due to less hazardous after-effect on environmental safety and it also gives high adsorbent yield [24].…”