Nanostructured and surface functionalized corncob as unique adsorbents for anionic dye remediation

Abstract

This study describes synthesis and characterization of corncob (CC), corncob nanocellulose (CCNC) and functionalized corncob (FCC) as unique adsorbents for methyl orange (MO) removal. Nanocellulose was synthesized via H 2 SO 4 hydrolysis and functionalization was achieved using H 3 PO 4 . All adsorbents were characterized by scanning electron microscopy coupled with energy dispersive X-ray and Fourier transform infra-red spectroscopy. Functionalization modified surface chemistry (disappearance of OH and appearance of PO 4 3− ), increased percentage carbon by 41.42% and produced welldeveloped pores. Nanocellulose retained intrinsic chemical properties of corncob though more porous with enhanced surface functionality prompted by more intense functional groups peaks and appearance of SO 4 2− . Maximum adsorption of MO occurred at pH 3.01, 4.11 and 2.09 for CC (54.34%), FCC (77.1%) and CCNC (96.81%) respectively. Adsorption parameters were fitted to four adsorption isotherms with Langmuir being the most appropriate to describe the adsorption process. Adsorption capacity increased from 17.86 mg g −1 in corncob to 60.82 mg g −1 in FCC and 206.67 mg g −1 in CCNC implying CCNC had the highest adsorption quality. The rate of adsorption was most accurately predicted by pseudo first order kinetics. Adsorption mechanism was governed by film diffusion with contribution from intra-particle diffusion. Adsorption process was spontaneous (− ∆G o ) at all temperatures (303-315 K), exothermic (− ∆H o ) and physical on CC (3.73 kJ mol −1 ) and CCNC (3.42 kJ mol −1 ) however it was endothermic (+ ∆H o ) and chemical on FCC (12.86 kJ mol −1 ). This study shows that CCNC is comparatively the best adsorbent with highest adsorption capacity.

Synthesis, Characterization and Anionic Dye Sequestration Capacity of Cellulose Nanocrystals Derived From Sugarcane Bagasse: Experimental and Regression Modelling

“…The method of synthesis as described by Adejumo et al (2020) was followed and is illustrated in the scheme (Figure 1). Fourier transform infrared spectroscopy (FTIR) (Model 500, Buck Scientific Inc.) was recorded in the range of 400-4000 cm -1 with a resolution of 4 cm -1 .…”

“…Most pollutants that found their way into water bodies are non-easily biodegradable, recalcitrant, stable to oxidation and are as dangerous as their intermediates and secondary metabolites (Jiang et al 2017;Gautam et al 2019;Beh et al 2020). Methyl orange (MO) is a complex, highly water soluble, azo-structured anionic dye that has found usefulness in laboratories, photography and textile but its discharge in water has been reported to interrupt ecological balance along with disruption of water quality parameters (Keyhanian et al 2016;Huang et al 2017;Zhang et al 2017;Adejumo et al 2020). Hence, holistic approaches to removing highly toxic MO should be employed to meet up with water demands of the populace.…”

“…Nanocellulose has found usefulness in medicine, food and construction applications in addition to the environmental remediation of wastes due to its biocompatibility, tensile strength, abundant hydroxyl groups, large surface area and low toxicity (Dufresne, 2013;Hosseinidoust et al 2015;Jorfi and Johan, 2015;Abitbol et al 2016;Hakkarainen et al 2016;Phanthong et al 2018;Wang et al 2019). It has been deployed for remediating dyes, volatile organic compounds, polycyclic aromatic hydrocarbons, heavy metals and pollutants of their likes (Chan et al 2015;Jiang et al 2017;Adejumo et al 2020;Beh et al 2020).…”

“…Cellulose nanocrystals extracted by acid hydrolysis treatment have been extensively explored and are considered easier compared with other methods of nanocellulose syntheses (Jonoobi et al 2015;Nechyporchuk et al 2016;Oliveira et al 2016;Theivasanthi et al 2018). Nanocellulose has been prepared from widely available, abundant, cost-effective and renewable cellulosic materials such as corncob, corn straw, pineapple leaf, cassava bagasse, cotton, soy hulls, sago pith, kenaf core, rice straw, cocoa bean shell, bamboo, wood, banana leaf, newspaper, jute leaf, groundnut shell, wheat straw, sugarcane bagasse and flax fibre (Abraham et al 2011;Neto et al 2013;Pehlivan et al 2013;Chan et al 2015;Chen et al 2011Chen et al , 2015Bano and Negi, 2017;El Achaby et al 2018;Theivasanthi et al 2018;Buthiyappan et al 2019;Adejumo et al 2020;Beh et al 2020) Sugarcane bagasse is a lignocellulosic fibrous residual waste from sugarcane (Saccharum officinarum) after sequencing its juice. It is widely available and litters carelessly in water and soil in Nigeria.…”

“…Extraction of nanocellulose from sugarcane bagasse is a better alternative owing to nondisruption of inherent chirality, available functional groups, biodegradability and biocompatibility with large surface area, enhanced surface functionality and adsorptive properties (Theivasanthi et al 2018;Adejumo et al 2020;Beh et al 2020).…”