Abstract

Currently, in different regions of the world, there is a growth on the rate of produced water for each barrel of oil extracted. Among the compounds observed in this water are naphthenic acids (NAs). Efforts to remove NAs from produced water must comply with local legislation and avoid damage to the environment since NAs have great toxicity. This study aimed to investigate the ability of activated carbon from the pericarp of babassu coconut (Atallea speciosa Mart. ex Spreng.) to act as an absorbent of NAs in commercial and natural (offshore) produced waters. The activated carbon was physically and chemically characterized. The maximum adsorption capacity of commercial NAs at equilibrium obtained experimentally was 25 mg g⁻¹. The activated carbon removed both NAs and other contaminants for produced water, as revealed by infrared and NMR techniques. In high-resolution mass spectrometry analysis, the abundance of the acids in the produced water was in the C9 and C10 range, being favorable for the adsorbent with a microporous structure. For the produced water kinetics experiments a maximum amount of adsorbed compounds of 17.91 mg g⁻¹ was reached, and the time to achieve equilibrium was approximately 180 min. Thus, the results show that activated charcoal from babassu coconut pericarp can be used as an adsorbent and can potentially compete with other adsorbents to remove NAs in an aqueous solution. Also, the separation process can be adopted at a low cost on platforms, complementing the operations of hydrocyclones and flotation.

摘要

目前，在世界不同地区，每提取一桶石油的采出水率都在增长。在这种水中观察到的化合物包括环烷酸 (NAs)。从采出水中去除 NA 的工作必须遵守当地法规，并避免对环境造成破坏，因为 NA 具有很强的毒性。本研究旨在研究巴巴苏椰子 ( Atallea speciosa Mart. ex Spreng.) 果皮中的活性炭在商业和天然（近海）采出水中充当 NA 吸收剂的能力。对活性炭进行了物理和化学表征。实验获得的平衡状态下商业 NA 的最大吸附容量为 25 mg g ^-1. 正如红外和 NMR 技术所揭示的那样，活性炭去除了采出水中的 NA 和其他污染物。在高分辨率质谱分析中，采出水中酸的丰度在C9和C10范围内，有利于具有微孔结构的吸附剂。对于采出水动力学实验，吸附化合物的最大量达到 17.91 mg g ^-1，达到平衡的时间约为 180 分钟。因此，结果表明，巴巴苏椰子果皮中的活性炭可用作吸附剂，并可能与其他吸附剂竞争去除水溶液中的 NA。此外，分离过程可以在平台上以低成本采用，补充了水力旋流器和浮选的操作。