# Effective Adsorption of Phenoxyacetic Herbicides by Tomato Stem-Derived Activated Carbons
## 1 Introduction  
Modern agriculture, forestry, and horticulture rely heavily on pesticides, with their use projected to escalate due to global food demand, the increased production of renewable energy and engineering materials, and the emergence of new pests and diseases. In 2022, according to the Food and Agriculture Organization, total pesticide use in agriculture reached 3.70 million tons [1]. This reflects a doubling of use since 1990, a 13% increase over the past decade, and a 4% increase from 2021. Compared to the 1990s, global pesticide use has increased by 121% for herbicides, 54% for fungicides and bactericides, and 48% for insecticides over the last decade [1]. The widespread use of these pollutants makes them one of the most serious environmental pollutants. They readily contaminate surface and groundwater through runoff and infiltration, negatively impacting aquatic ecosystems [2,3]. Herbicides currently constitute the largest group of pesticides in use, accounting for 56%, followed by fungicides at 25% and insecticides at 19% [1]. After glyphosate, the derivatives of phenoxyacetic acid, 2,4-dichlorophenoxyacyacetic acid (2,4-D), and 2-methyl-4-chlorophenoxyacyacetic acid (MCPA) represent the most commonly used herbicides [3]. Thesetwo primary herbicides, designed to control broadleaf weeds in crops, pose a risk to aquatic environments due to their toxicity to living organisms [3; 4]. Consequently, their degradation and removal from the ecosystem are a priority. Adsorption is a prevalent water purification technique, valued for its high efficiency, operational simplicity, and broad applicability [3; 5; 6; 7; 8]. Activated carbon (AC) is a commonly used adsorbent, particularly in granular form. The high cost of commercially available activated carbon (AC) is primarily due to expensive production processes and non-renewable precursors such as coal, peat, and petroleum coke [9]. Consequently, researchers are investigating renewable, readily available, and inexpensive raw materials as alternative precursors for AC production. Low cost, renewability, and availability make biomass precursors particularly promising raw materials [3; 10; 11]. Recent research has explored numerous activated carbons, including those synthesized from wood, agricultural waste, and industrial biomass [10; 11]. Plant-derived AC has been produced from various components, including peels, stems, shells, and other agricultural residues. These materials, primarily composed of cellulose biopolymers and other high-carbon-content polysaccharides, are suitable precursors for AC production. Lignocellulosic biomass offers an environmentally friendly and advantageous source for AC production. These precursors are diverse, readily available, and renewable, and their high reactivity simplifies the synthesis process [3; 10]. In addition, it is also a reliable way to manage agricultural and household waste, which contributes to reducing disposal costs and negative environmental impacts. Various parts of plants can be used to produce AC. This study explores the production of activated carbon from tomato stems (TS-AC) using a novel two-step process: pyrolysis followed by combined potassium hydroxide (KOH) and sodium hydroxide (NaOH) chemical activation. While previous research has examined TS-AC's properties, this work distinguishes itself through the specific activation methodology. Recently, [PERSON] et al. [12] used the lotus petiole biomass in AC production, [PERSON] et al. [13] used palm shells as a precursor, [PERSON] et al. [14] used rubber fruit shells, and [PERSON] et al. [15] used the coconut shell. In all these works, KOH was used as the activation medium. The activating agent-to-precursor ratio often ranged from 1:1 to 4:1. In the work of [PERSON] et al. [16], KOH precursor mass ratios of 2, 3, or 4 were selected. [PERSON] et al.