Synthesis of Porous Biochar Containing Graphitic Carbon Derived From Lignin Content of Forestry Biomass and Its Application for the Removal of Diclofenac Sodium From Aqueous Solution

Abstract

Porous biochar containing graphitic carbon materials have received great attention from various disciplines, especially for environmental pollutant treatment, due to their cost-effective and specific textural properties. This study exhibited a two-step strategy to compose lignin-porous biochar containing graphitic carbon (LPGC) from pitch pine sawdust and investigated its adsorptive removal for diclofenac sodium (DCF) from an aqueous solution. Sulfuric acid (H 2 SO 4 ) was utilized to obtain lignin content from biomass and potassium ferrate (K 2 FeO 4 ) and was adopted to fulfill the synchronous carbonization and graphitization of LPGC. Through slow pyrolysis in atmospheric N 2 (900 • C -2 h), the structure of the as-prepared sample was successfully modified. Using SEM images, a stripped layer structure was observed on the H 2 SO 4 -treated sample for both one-step and two-step activated samples, indicating the pronounced effect of H 2 SO 4 in the layering of materials. K 2 FeO 4 acted as an activator and catalyst to convert biomass into the porous graphitic structure. The BET surface area, XRD and Raman spectra analyses demonstrated that LPGC possessed a micro/mesoporous structure with a relatively large surface area (457.4 m 2 g −1 ) as well as the presence of a graphitic structure. Further adsorption experiments revealed that LPGC exhibited a high DCF adsorption capacity (q max = 159.7 mg g −1 at 298 K, pH = 6.5). The effects of ambient conditions such as contact time, solution pH, temperature, ionic strength, electrolyte background on the uptake of DCF were investigated by a batch adsorption experiment. Results indicated that the experimental data were best fitted with the pseudo second-order model and Langmuir isotherm model. Furthermore, the adsorption of DCF onto the LPGC process was spontaneous and endothermic. Electrostatic interaction, H-bonding interaction, and π-π interaction are the possible adsorption mechanisms. The porous biochar containing graphitic carbon obtained from the lignin content of pitch pine sawdust may be a potential material for eliminating organic pollutants from water bodies.

Recent advances in the valorization of plant biomass

“…Bio-char has received more attention in recent years, and several reviews have summarized its production [ 101 , 154 – 157 ]. Bio-char presents porous structure, abundant functional groups, high surface area, which includes minerals and trace metals [ 158 ], so it shows a wide range of applications, including adsorption (chemical substances [ 159 , 160 ], dye [ 161 , 162 ], and heavy metals [ 17 , 163 , 164 ]), catalysis [ 165 – 168 ], soil repair [ 163 , 169 ], and use as building materials [ 170 ], electrochemical energy storage [ 171 – 173 ], etc. During the process of bio-oil or bio-char production, syngas containing hydrogen, carbon monoxide, methane, etc.…”

Fabrication of Partially Graphitic Biochar for the Removal of Diclofenac and Ibuprofen from Aqueous Solution: Laboratory Conditions and Real Sample Applications

“…Various methodologies have been developed to remove DCF and IBU from water bodies such as electrochemical degradation (Pourzamani et al, 2018), chlorination (Simazaki et al, 2008), advanced oxidation processes (Perisic et al, 2016;Saeid et al, 2018), ozonation (García-Araya et al, 2010; Quero-Pastor et al, 2013), photodegradation (Chianese et al, 2016;Tanveer et al, 2019), membrane filtration (Shojaee Nasirabadi et al, 2016), ultrasonic irradiation (Nie et al, 2014), and adsorption (Ghemit et al, 2019;Phasuphan et al, 2019;Tam et al, 2020). Among those mentioned techniques, adsorption has gained much attention from environmentalists and researchers because of its simplicity, less time consuming, reliability, and low cost (Yin et al, 2018).…”