Physicochemical Properties and Application of Silica-Doped Biochar Composites as Efficient Sorbents of Copper from Tap Water

Abstract

This article concerns research on new sorption materials based on silica-doped activated carbon. A two-stage synthesis involved pyrolysis of plant material impregnated in a water glass solution, followed by hydrothermal activation of the pyrolysate in KOH solution. The resulting composite can be used as a sorbent in drinking water filters. The proposed method of synthesis enables the design of materials with a surface area of approximately 150 m2·g−1, whose chemical composition and structure were confirmed by scanning electron microscopy/energy dispersive spectroscopy (SEM/EDS), X-ray diffraction (XRD), thermogravimetry/differential thermal analysis (TG/DTA) and Fourier-transform infrared spectroscopy (FTIR). The sorption properties of the obtained materials were determined relative to copper ions using the batch experiment method. The optimal operating parameters of the obtained materials relative to copper ions are T = 313.15 K, pH = 5, S:L ratio = 4 g·dm−3 and t = 120 min. The research shows that the sorption kinetics of copper ions can be described by a pseudo-second-order model. The plotted copper(II) sorption isotherm clearly indicates the Langmuir model. Under optimal conditions, the maximum sorption of copper ions was 37.74 mg·g−1, which is a satisfactory result and confirms the possibility of using the obtained material in drinking water filters.

The Application of Pyrolysis Biochar Obtained from Waste Rapeseed Cake to Remove Copper from Industrial Wastewater: An Overview

“…The material obtained in the pyrolysis process at a temperature of 700 • C proved to be non-porous, with a specific surface area of 0.35 m 2 •g −1 . There are few functional groups on its surface, which is why it has relatively weak adsorption properties [48][49][50].…”

“…Biochar 3-rapeseed cake was impregnated with 3M potassium silicate solution [50]. The mixtures were then left for 72 h at room temperature so that excess water could evaporate.…”

“…This article summarises and compares the methods used to modify waste rapeseed cake and the properties of the carbon materials obtained from it, with particular emphasis on sorption and separation properties relative to the copper(II) ion [48][49][50]. The importance and purposefulness of this study are justified by the fact that copper deposits are being depleted in the world, and the demand for this metal is increasing.…”

Preparation of ZnMgAl-Layered Double Hydroxide and Rice Husk Biochar Composites for Cu(II) and Pb(II) Ions Removal from Synthetic Wastewater

“…The development of innovative technologies to purify industrial effluent before it is released into waterways is required. Microbial (microalgae) fuel cell technology, membrane technology, and solar irradiation are some of the new wastewater treatment technologies 2 of 17 that have yet to mature [5][6][7]. Reverse osmosis, chemical precipitation, ion exchange, and adsorption are just a few well-known technologies that have been frequently used in order to eradicate heavy metals from industrial wastewater [8,9].…”

“…In the adsorption process, the selection of adsorbent plays an important role in achieving maximum efficiency [13]. In recent years, biochar (BC), activated carbon, silica-based sorbents, metal-organic frameworks (MOFs), clay composites, natural polymer, resins, montmorillonite, nanomaterials, and layered double hydroxides (LDHs) have provided the best results for Cu(II) and Pb(II) ions remediation in wastewater [14][15][16][17][18][19][20][21][22][23][24][25][26].…”