Hoc Thang Nguyen, Sy Khang Dinh, Duy Hai Tran, Thi Nga Dinh, Dinh Tuan Phan
Department of Materials Technology, Faculty of Chemical Technology, Ho Chi Minh City University of Food Industry 140 Le Trong Tan Street, Tan Phu District Ho Chi Minh City Vietnam.
Faculty of Environment, Ho Chi Minh City University of Natural Resources and Environment 236B Le Van Sy Street, Tan Binh District Ho Chi Minh City Vietnam
RSC Adv. 2021 Aug 3;11(43):26563-26570. doi: 10.1039/d1ra04672a. eCollection 2021 Aug 2.
Activated carbon produced from agricultural products and wastes has been applied widely to remove pollutants in the field of waste water treatment. However, the cost of this adsorbent depends so much on the raw material sources. Therefore, the approach of producing activated carbon from agricultural waste is strongly recommended due to economic advantages and environmental protection. One of the potential feed-stocks for the activated carbon production is cashew nut shell (CNS) waste which could reduce the negative impacts to the environment from the cashew nut processing industry and simultaneously enhance the values of the related products. This study focused on evaluating the influences of variable factors, such as activation temperature and time, on the properties of the activated carbon obtained from CNS. Methylene blue (MB) adsorption was applied to understand the adsorption mechanism of the products. The results show that increasing the activation temperature led to a rise in the adsorption capacity of the activated carbon within the temperature range of 800 to 850 °C. Otherwise, the values were reduced when the temperature was greater than 850 °C and this was related to the thermal decomposition of carbon. The adsorption capacity also increased when the activation time was changed from 30 min to 50 min. However, in the activation time range from 50 to 70 min, there was a reduction of the adsorption capacity of CNS-based activated carbon. The results also show that the MB adsorption of the activated carbon occurred with one-site-occupancy in the first layer and then layer-by-layer adsorption formation.
由农产品和废弃物制成的活性炭已在废水处理领域广泛应用于去除污染物。然而，这种吸附剂的成本在很大程度上取决于原材料来源。因此，鉴于经济优势和环境保护，强烈推荐采用农业废弃物生产活性炭的方法。腰果壳（CNS）废弃物是生产活性炭的潜在原料之一，它可以减少腰果加工行业对环境的负面影响，同时提高相关产品的价值。本研究着重评估诸如活化温度和时间等可变因素对从CNS获得的活性炭性能的影响。采用亚甲基蓝（MB）吸附来了解产品的吸附机制。结果表明，在800至850℃的温度范围内，提高活化温度会导致活性炭吸附容量增加。否则，当温度高于850℃时该值会降低，这与碳的热分解有关。当活化时间从30分钟变为50分钟时，吸附容量也会增加。然而，在50至70分钟的活化时间范围内，基于CNS的活性炭吸附容量有所降低。结果还表明，活性炭对MB的吸附首先在第一层发生单点位占据，然后形成逐层吸附。
