Synthesis, Characterization, and Dye Removal of ZnCl₂-Modified Biochar Derived from Pulp and Paper Sludge

Abstract

In this study, pulp sludge-derived biochar synthesized through modification with ZnCl 2 under multistep pyrolysis conditions was investigated for the effective removal of methylene blue (MB) from aqueous solution. Results showed that when the Zn2PT350-700 dosage was 10 mg, the largest adsorption amount of MB was 590.20 mg/g within 24 h under pH = 8. Kinetics and thermodynamics revealed that the adsorption process of MB can be described by the Freundlich isotherm model and the pseudo-second-order kinetic model, which means that multilayer sorption occurred on the heterogeneous surface of Zn2PT350-700. The analysis of the adsorption mechanism showed that electrostatic attraction between the deprotonated functional groups and MB + , cation exchange, and π-electron interaction played a major role in MB adsorption, followed by physical adsorption. After six cycles of desorption–adsorption, Zn2PT350-700 still maintained good adsorption performance. All results demonstrated that Zn2PT350-700 could perform as promising adsorbents for efficient MB removal from wastewater. Using biochar from paper and pulp sludge for wastewater remediation is an ingenious method, which can reduce the environmental and health risks related to industrial waste disposal, while providing remediation of water contaminated with industrial dye effluents.

Valorization of Ginger Waste-Derived Biochar for Simultaneous Multiclass Antibiotics Remediation in Aqueous Medium

“… 24 , 25 In recent times, it has been used as an efficient chemical activation agent for the fabrication of the porous carbonaceous material from a varied range of biomasses. 26 The differential adsorption behaviors of non-activated and activated biochar were in agreement with the obtained BET and SEM data.…”

“…The non-activated biochar was less efficient in the removal of antibiotics in comparison to AGB (results not mentioned). ZnCl 2 being a Lewis acid is used as a dehydration agent for specific removal of the H and O from biomass to prevent the tar formation resulting in increased high surface area, active sites, and biomass porosity. , In recent times, it has been used as an efficient chemical activation agent for the fabrication of the porous carbonaceous material from a varied range of biomasses . The differential adsorption behaviors of non-activated and activated biochar were in agreement with the obtained BET and SEM data.…”

“…The hysteresis loop from the BET plot for the adsorption and desorption of N 2 in activated ginger biochar corresponding with H4 type (in reference to IUPAC classification) suggested the presence of micro as well as mesopores promoting a favorable and efficient adsorptive removal ( Figure 1 A). 26 Thermogravimetric curve for the activated biochar showed a weight loss of approximately 20 per cent up to 115 °C, while the weight remained nearly constant up to 400 °C. Again, the loss in weight was observed from 400 to 900 °C and attaining equilibrium thereafter.…”

“…The increased surface area and porosity of the AGB supported enhanced adsorption capacity of the AGB compared to the native biochar. The hysteresis loop from the BET plot for the adsorption and desorption of N 2 in activated ginger biochar corresponding with H4 type (in reference to IUPAC classification) suggested the presence of micro as well as mesopores promoting a favorable and efficient adsorptive removal (Figure A) . Thermogravimetric curve for the activated biochar showed a weight loss of approximately 20 per cent up to 115 °C, while the weight remained nearly constant up to 400 °C.…”

Mono- and Multicomponent Biosorption of Caffeine and Salicylic Acid onto Processed Cape Gooseberry Husk Agri-Food Waste

“…In addition, the presence of a band at 1722–1732 cm –1 in the spectrum of H indicates the presence of a C=O, which gets weakened in the spectrum of H350 and disappears in the spectrum of H500 consistent with the carbonization and CO 2 release during the activation process. The bands at 1610–1650 cm –1 in the three husks correspond to either the C=C alkene stretch or the deformed bending vibrations of the adsorbed water molecules, 32 − 34 while the bands at 2300 cm –1 along with the bands at 650 cm –1 in H350 and H500 could be assigned to the adsorbed CO 2 . 22 It can also be observed that the intensity of the CO 2 bands in the spectrum of H350 is higher than their counterparts in the H500 spectrum.…”