Removal of Pb2+ from industrial wastewater using activated carbon from Persea americana seed

Abstract Activated carbon is a material that has various environmental applications, such as the adsorption of metallic lead ions (Pb2+). It can be obtained from different plant species. In this research, the seed of Persea americana (Avocado- HASS variety) was obtained from local markets in the city of Cartagena to be used in the removal of Pb2+ from wastewater from the fishing industry. To obtain activated carbon, the seed was carbonized in a Terrigeno-brand clay oven, Model DB 1200. Orthophosphoric acid at 21% w/v was used as an activating agent. The residual water was characterized following the APHA specifications. The turbidity was determined by nephelometry in a Turbiquant 300 IR turbidimeter. The Pb2+ concentration was determined by atomic absorption spectroscopy in a Thermo Scientific iCE 3300 equipment. The chemical surface of the material was performed by Fourier transform infrared spectroscopy (FTIR). The carbons were morphologically characterized using a scanning electron microscope SEM (Jeol 5910LV), visualized at 15kV. A yield of 20.38% by mass of coal is achieved. The pores are of irregular size, ranging from 16.2 to 55.98 μm. 65% of Pb2+, turbidity (57.6%), color (57%), total solids (50.2%), as well as BOD (53.12%) and COD (36%) are removed, finding statistically significant differences in values at the 95% level of significance. The seed of Persea americana (HASS avocado) can serve as plant material to obtain an adsorbent material (activated carbon) and be used in the removal of Pb2+ from wastewater.

摘要：活性炭是一类具备多样环境应用场景的功能材料，可用于吸附金属铅离子（Pb²+）。该材料可由多种植物原料制备得到。本研究以取自卡塔赫纳市本地市场的哈斯（HASS）品种鳄梨（Persea americana）的种子为原料，用于去除渔业废水中的Pb²+。为制备活性炭，将该种子在Terrigeno品牌、型号为DB 1200的黏土炉中进行炭化，并采用21%质量体积比的正磷酸（Orthophosphoric acid）作为活化剂。依照美国公共卫生协会（APHA）规范对处理后的残留废水开展表征工作：采用浊度法在Turbiquant 300 IR型浊度仪上测定废水浊度；采用原子吸收光谱法在赛默飞世尔科技（Thermo Scientific）iCE 3300型设备上测定Pb²+浓度；通过傅里叶变换红外光谱（FTIR）表征材料的表面化学特性；借助扫描电子显微镜（SEM，Jeol 5910LV型）对活性炭的形貌进行表征，加速电压设置为15kV。实验结果显示，该活性炭的质量产率为20.38%，其孔径尺寸不规则，分布区间为16.2~55.98 μm。该吸附剂可实现65%的Pb²+、57.6%的浊度、57%的色度、50.2%的总固体、53.12%的生化需氧量（BOD）以及36%的化学需氧量（COD）的去除，且在95%显著性水平下，各指标去除率均存在统计学显著差异。本研究表明，哈斯鳄梨种子可作为制备吸附剂（活性炭）的植物原料，用于去除废水中的Pb²+。