## 1 Introduction
[15] reported MB adsorption capacities were 200 mg/g with a bituminous-based GAC and 196 mg/g with a sucrose-based GAC. Finally, a comparison of three different commercially available GACs with particle sizes ranging from 400 to 1680 \(\upmu\)m for removal of RhB reported adsorption capacities of between 260 and 319 mg/g [16]. There is a push to produce sustainable and environmentally friendly GAC by sourcing it from a variety of materials; however, current research indicates that the variation in starting material still renders its adsorption capacity somewhat inconsistent for the broad range of molecular sizes and structures present in synthetic dyes. In addition to the impact of the source material on GAC, the choice of activating chemical agent and activation method plays an important role in GAC performance. [PERSON] et al. reported a higher adsorption capacity of Bagasse pith-based GAC--which was chemically activated with H\({}_{3}\)PO\({}_{4}\), with a capacity of 198.6 mg/g for RhB removal--compared to the same material activated with KOH, which only had a capacity of 21.5 mg/g [17]. Later, a comparison of different chemically activated Acacia wood-based GAC with different agents indicated a considerable alteration in adsorbents' morphology and structure. This led to a 26-times higher adsorption capacity of GAC activated with H\({}_{3}\)PO\({}_{4}\) (76.6 mg/g) compared to the GAC activated with CaO (2.9 mg/g) for removal of RhB [18]. However, the rate of removal for GAC-based systems has been reported to be slow at times [18]. Given the diverse molecular structures and sizes of synthetic dyes and the restrictions and limitations of GAC and NaY in effectively adsorbing these dyes, there is a growing need to explore alternative removal methods that are more robust, especially considering the increasing uncertainty regarding water quality resulting from climate change. Graphene oxide (GO) has a layered structure, with an abundant number of oxygen-containing functional groups including carboxyl, hydroxyl, and epoxide reporting high adsorption capacity and robust adsorption of various organic contaminants including synthetic dyes [19; 20]. Further, GO has demonstrated potential as a robust adsorbent in various applications, such as land remediation, energy storage, and water/wastewatertreatment [21]. [PERSON] et al. [22], reported 99.4% removal of MB with 714 mg/g maximum adsorption capacity. Additionally, the functionalization of beta zeolite with GO resulted in a substantial improvement in adsorption capacity from 27.9 mg/g to 64 mg/g for the removal of RhB, highlighting the potential of GO as an alternative adsorbent [8]. However, limited studies are available to compare the potential of GO against GAC and NaY. However, a study by [PERSON] et al. [23] demonstrated 103 mg/g adsorption capacity for GO for the removal of tetramethylmonium hydroxide (TMAH) from water, compared to 30.1 mg/g with GAC, and 59.3 mg/g with NaY under slow mixing conditions (175 rpm) for a 5 h time period, demonstrating the potential of GO for removal of dyes. The results of surface area measurement with N\({}_{2}\) BET indicated that a higher volume of mesopores in GO led to a higher adsorption capacity for removal of TMAH compared to NaY and GAC [23]. A recent study also reported that GO outperformed GAC in the removal of some heavy metals in surface waters; for example, iron, fluoride, and arsenic, with respective removals of 84.5% vs. 70.7% (Fe), 73% vs. 58% (Fl), and 91% vs. 82% (Ar) [24]. The current study fills a gap in the literature by conducting a comparative study of the removal efficiency of GO against commonly used adsorbents, GAC and NaY, for the removal of synthetic dyes, particularly in relation to investigating their structural characteristics and adsorption behaviour under slow mixing conditions.