Successful Application of Eucalyptus Camdulensis Biochar in the Batch Adsorption of Crystal Violet and Methylene Blue Dyes from Aqueous Solution

Abstract

Eucalyptus camdulensis biochar (Ec-bio) was used to adsorb crystal violet (CV) and methylene blue (MB) dyes, which was optimized and further evaluated using different isotherm and kinetic models. Microscopy and spectroscopy techniques showed the interactions of the dyes with the surface functional groups of the Ec-bio, resulting in the removal of the dyes from aqueous solution. Both dyes were immediately uptaken, with equilibrium reached in 60 min, with a higher sorption efficiency of CV compared to MB. Thermodynamic parameters showed endothermic adsorption and the nonspontaneous adsorption of both dyes onto the Ec-bio. Both the adsorption capacity and percentage removal increased with the increasing solution pH from 2.0 to 4.0 and to 10 for CV and MB. An increase in adsorption capacity was observed upon increasing the initial concentrations, with a corresponding decrease in the percentage removal. The pseudo-second-order (PSO) and Elovich kinetic models (nonlinear approach) were a good fit to the data of both dyes, confirming a chemisorptive adsorption process. The Langmuir isotherm fitted well to the CV data, supporting its monolayer adsorption onto the Ec-bio, while the Freundlich isotherm was a good fit to the MB dye data, suggesting the surface heterogeneity of the Ec-bio. The Dubinin–Radushkevich isotherm was a good fit to the adsorption CV data compared with the MB dye, suggesting the physisorption of both dyes onto the Ec-bio due to its mean free energy of adsorption of <8 kJ mol−1.

Fabrication and Characterization of Effective Biochar Biosorbent Derived from Agricultural Waste to Remove Cationic Dyes from Wastewater

“…Table 5 illustrates the maximum adsorption capacities of MB-dye and CV-dye onto various types of natural biochars [1,22,24,28,33,[59][60][61][62]. The results represented in this table shows that the fabricated T-BC have considerable adsorption capacities comparing with other published works.…”

“…Phosphoric acid and Zinc chloride are two of the most often used activating agents in chemical activation, aside from NaOH and KOH [20,21]. Therefore, many research studies have been published during the last couple of years investigating the use of biochar to adsorb dyes and in wastewater treatment processes [22][23][24][25][26][27][28][29][30][31][32][33]. CV and/or MB dyes were adsorbed from aqueous media by various types of biochar such as eucalyptus camaldulensis biochar (Ec-bio) [22], porous biochar [23], mesoporous seaweed biochar [24], castor biomass-based biochar [25], adsorbents from orange peel residues [26], biochar at different carbonization times [28], date palm fronds biochars [31], and rice husk-mediated magnetic biochar (RH-MBC) [33].…”

Synthesis of a novel perovskite-carbon aerogel hybrid adsorbent with multiple metal-Lewis active sites for the removal of dyes from water: experimental and DFT studies

“…The K d value of Sr 0.7 Mn 0.3 Co 0.5 Fe 0.5 O 3Àd /CAg was higher in comparison to other adsorbents in the literature. 7,[35][36][37][38][39][40] It was found that the DB-perovskite/CAg hybrid leads to a higher K d than other adsorbents, suggesting higher retention and low mobility of CV and AY17 in an aqueous solution. The CV molecules have smaller sizes than AY17.…”

Ethylenediaminetetraacetate functionalized MgFe layered double hydroxide/biochar composites for highly efficient adsorptive removal of lead ions from aqueous solutions

“…Eb was prepared as reported previously [ 31 ], using Ec waste obtained from local areas around the city of Riyadh, Kingdom of Saudi Arabia. The collected waste was washed rigorously and thoroughly dried in an open atmosphere, and then the oven-dried (at 80°C for 6 hours) product was crushed in a ball mill to obtain an average particle size of nearly 5.0 mm.…”