Sustainable Materials and Technologies 35 (2023) e00525 Available online 19 November 2022 2214-9937/© 2022 Elsevier B.V. All rights reserved. Novel green biodegradable clarifying agents in sugar refning process using functionalized chitosan nanocomposites Ahmed S. Ibrahim a , Ahmed N. Gad b , Hemat M. Dardeer c , Abdel-Aal M. Gaber d, * a Faculty of Sugar and Integrated Industries Technology, Assiut University, Egypt b Research and Development Center of ESIIC, Quos, Egypt c Chemistry Department, Faculty of Science, South Valley University, Qena, Egypt d Chemistry Department, Faculty of Science, Assiut University, Assiut 71516, Egypt A R T I C L E INFO Keywords: Sustainability Refning sugar Biomass waste Biodegradability Clarifcation ABSTRACT Clarifcation of sugar solutions without side-contaminants during sugar manufacturing is still the main challenge in sugar factories. Herein, chitosan-cellulose (CS-CEL) and chitosan-powder activated carbon (CS-PAC) nano- composites were synthesized to be used as green biodegradable clarifying agents in sugar refning process. PAC was obtained via physical activation procedures using water vapor at 950 ◦ C on carbonized sugarcane bagasse waste, then CS-PAC was combined using a cross-linking agent. Zeta potential analysis gave remarkable results for CS-CEL and CS-PAC with maximum values (+) 57.73 mV and (+) 41.1 mV, respectively, with improvement in color removal % up to 45.5% using CS-PAC and 45.1% using CS-CEL with >25% compared to traditional clarifcation process. Also, turbidity decreased from 167 IU to 2 IU using CS-CEL and CS-PAC. Overall, we found that CS-CEL and CS-PAC nanocomposites have considerable effciency in sugar refning process as eco-friendly bio-sorbents and focculating materials. 1. Introduction In the sugar industry, there are a variety of non-sugar compounds found in sugar process solutions that have a negative impact on sugar product quality. Colorants are a serious issue throughout the sugar production process. Because they impair the purity of white sugar and have a negative impact on crystallisation. There are two types of color in sugar industry natural and those formed during the sugar manufacturing process. Natural colorants exist in cane, such as chlorophylls and fa- vonoids, in addition to color manufactured in a factory such as melanins, melanoidins, hexose alkaline degradation products (HADP), and cara- mels [1,2]. As color is one of the most important criteria for judging the quality of sugar [1], thus, phosphotation and carbonation are frequently used in traditional methods for eliminating these color compounds. When compared to their negative impact on refned sugar quality, raw sugar quality features such as moisture, reducing sugars, and colorants are not regarded as substantial contributors to the ineffcient carbo- natation process and press fltering [3]. The sugar syrup obtained following this procedure, however, still contains color impurities, and this approach would produce calcium carbonate (CaCO 3 ) due to the reaction of carbon dioxide and milk of lime (Ca(OH) 2 ) [3]. Due to its simple design, cheap cost, ease of maintenance, and high performance, adsorption is a commonly used green separation technique [4]. Adsorption has been used in several research to remove color from sugar syrup. Biocompatibility, particle size, surface area, surface charge, particle charge, and hydrophilicity all have a signifcant impact on the effectiveness of nanomaterials as color adsorbents [5,6]. Sugar beet pulp, tea leaves, hazelnut shells, and orange peel have all been described as promising alternative adsorbents for effectively extracting the color components in sugar solutions [7]. Sugarcane bagasse, one of the most common agricultural by-products, is a promising raw material for making adsorbents since it is inexpensive [8], It has been used as an adsorbent directly for color removal in a few studies [9] or by converting it into activated carbon for higher adsorption and color removal capacity [10–13]. Moreover, carbon-based materials, such as carbon nanotubes, carbon fbers, graphene, powder activated carbon (PAC), and porous carbon, have long been used to remove organic contaminants from aqueous solutions. Because of their particular physicochemical features as they have large number of active sites with reasonable cost [14]. Biopolymers are gaining popularity due to large number of functional groups, envi- ronmental friendliness, and lack of toxicity. Chitosan (CS) is a form of * Corresponding author. E-mail address: gaber@aun.edu.eg (A.-A.M. Gaber). Contents lists available at ScienceDirect Sustainable Materials and Technologies journal homepage: www.elsevier.com/locate/susmat https://doi.org/10.1016/j.susmat.2022.e00525 Received 14 September 2022; Received in revised form 5 November 2022; Accepted 16 November 2022