The Use of Sugarcane Bagasse to Remove the Organic Dyes from Wastewater

Abstract

In the present study, the potential of sugarcane bagasse (SCB) was evaluated by methylene blue (MB) retention. The selected low-cost adsorbent was characterized by scanning electron microscopy (SEM) coupled with energy-dispersive X-ray spectroscopy (EDX), Fourier transform infrared spectroscopy (FTIR), BET method, and determination of the point of zero charge (pHzpc). Batch kinetic and isothermal studies were performed to examine the effects of contact time, initial dye concentration, adsorbent dose, pH, and temperature. The results show that the kinetic study of MB adsorption on sugarcane bagasse is very fast; the equilibrium is reached after only 20 minutes. The kinetic model of pseudo-second-order and the Langmuir isotherm model perfectly explain the adsorption process of MB with a monolayer adsorption capacity equal to 49.261 mg·g−1 activation parameters’ values such as free energy (ΔG°), enthalpy (ΔH°), and entropy (ΔS°) also determined as −4.35 kJ·mol−1, −31.062 kJ·mol−1, and −0.084 J·mol−1·K−1, respectively. Besides, the thermodynamic parameters of the methylene blue sugarcane bagasse system indicate that the exothermic adsorption process is spontaneous.

Valorization of sugarcane bagasse for sugar extraction and residue as an adsorbent for pollutant removal

“…Specifically, cellulase hydrolysis led to larger TV (from 0.004 to 0.01 cm 3 /g) and APS (from 47.5 to 122.1 nm) in SCBE, presumably resulting from the breakdown of cellulose chain by cellulase. In previous reports, without water extraction for soluble sugars, SCB was characterized non-porous or macro-porous based on the SSA of 0.73 m 2 /g, TV of 0.0007 cm 3 /g, and APS of 5.73 nm, respectively (Kerrou et al, 2021), which were apparently lower than the values in this study by 5 to 8 folds. It is apparent that prior water extraction of soluble sugars spares more pore space in SCB that is originally taken by sugar molecules.…”

“…For both MB and Cu 2+ , the adsorption by the four adsorbents was fast and equilibrium was reached within 60 min. Similarly, another study showed that adsorption of MB on SCB was reached in only 20 min ( Kerrou et al, 2021 ). In comparison of the two adsorbents, the time for adsorption equilibrium by SCBE was slightly shorter than that by SCB, even though SCBE showed reduced adsorption capacity, as revealed in the later section.…”

“…Enzymatic hydrolysis can be regarded as a kind of modification of SCB as its functional groups on the surface were significantly altered as shown in FTIR spectra ( Figure 4B ). In comparison to the original SCB, enzymatically hydrolyzed adsorbent (SCBE) showed the intensified absorption peak at 3419 cm −1 (-OH), 2927 cm −1 (-CH 2 asymmetric stretching), 1627 cm −1 (-C=O stretching), 1085 cm −1 (-C-OH vibration), and 600 cm −1 , while in the range of 2650 to 1750 cm −1 , the absorption intensity was notably weakened ( Bisla et al, 2020 ; Kerrou et al, 2021 ). The band at wavenumber of around 1748 cm −1 has been assigned to carbonyl groups ( Ezeonuegbu et al, 2021 ).…”

“…This demonstrates that different mechanisms might apply for adsorption of pollutants by SCB and SCBE. Some reports have observed a drastic decline in adsorption of MB by SCB along with the increasing temperature ( Kerrou et al, 2021 ). These results suggest the potential of using SCB or SCBE in removal of dyes and metal ions from wastewater.…”

“…These residual soluble sugars represent a significant amount and should not be overlooked, which has not been examined in some of the related literature ( Chourasia et al, 2021 ). For instance, bulk SCB collected from “sugarcane juice” vendors was only washed a few times to remove the surface impurities and then dried, ground, and sieved for further use ( Kerrou et al, 2021 ), possibly leaving behind additional sugars inside the biomass. Apart from soluble sugars, another problem associated with utilization of SCB is the less efficient and economical release of compositional sugars from lignocelluloses for biofuel generation via enzymatic hydrolysis with cellulase enzymes ( Martínez et al, 2009 ; Waclawovsky et al, 2010 ; Liu et al, 2015 ).…”