Abstract：
An efficient and economical way of eliminating fluoride from water is being investigated by employing the buoyant aquatic plant (Dal weed). Two post-pyrolysis chemical activation alteration techniques were implemented: acidic activation by employing sulfuric acid (H-activation) and alkaline activation using sodium hydroxide (OH-activation). The batch kinetic studies have been carried out considering varying starting fluoride levels such as 2 - 10 mg/L. The impact of diverse procedural factors, including dosage of Dal weed, starting fluoride level, pH and contact duration was observed to determine their influence on fluoride adsorption kinetics. Based on analyzed exploratory results, removal efficacy of 63% for the OH-activated carbon and 83% for H-activated carbon was achieved at commencing fluoride level of 10 mg/L, adsorbent dosage of 0.8 g, at 25 °C after 120 minutes. The maximal fluoride uptake capacity for H-activated carbon was observed to be 78.158 mg/g. Kinetic investigations showed that the Freundlich isotherm model provided a satisfactory match with an R2 value of 0.99. The reaction order nature adhered to kinetics resembling pseudo second order. Thermodynamic investigation revealed endothermic sorption, with negative ΔG indicating spontaneous fluoride uptake. In comparison, the positive number for ΔS suggested random behavior at the contact involving the adsorbent and adsorbate. The investigations into the regeneration capabilities of the adsorbent material revealed that even after undergoing for five consecutive cycles of adsorption and regeneration, the adsorbent exhibited an uptake potential of 45%. The presence of competing ions in the solution negatively impacted defluoridation efficacy, with the influence following the order of HCO3-< NO3-< Cl-< SO42-< PO43-.
摘要：
正在研究通过使用浮力水生植物（Dal杂草）从水中消除氟化物的有效且经济的方法。实施了两种热解后化学活化改变技术：使用硫酸进行酸性活化（H活化）和使用氢氧化钠进行碱性活化（OH活化）。考虑到不同的起始氟化物水平，例如2-10mg/L，已经进行了分批动力学研究。不同程序因素的影响，包括Dal杂草的剂量，起始氟化物水平,观察pH和接触持续时间以确定它们对氟化物吸附动力学的影响。根据分析的探索性结果，在开始氟含量为10mg/L时，OH-活性炭的去除率为63％，H-活性炭的去除率为83％，吸附剂用量0.8g，在25°C下120分钟后。观察到H-活性炭的最大氟化物吸收能力为78.158mg/g。动力学研究表明，Freundlich等温线模型提供了令人满意的匹配，R2值为0.99。反应顺序性质与动力学类似，类似于伪二阶。热力学研究显示吸热吸附，负ΔG表示自发的氟化物吸收。相比之下,ΔS的正数表明在涉及吸附剂和被吸附物的接触处具有随机行为。对吸附材料的再生能力的研究表明，即使在经历了五个连续的吸附和再生循环之后，吸附剂表现出45%的吸收潜力。溶液中竞争离子的存在对除氟效率产生负面影响，其影响遵循HCO3-
