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. Keywords: activated carbon, adsorption, avocado seeds (HASS variety), Pb2+, removal.

Many substances of plant origin are extracted for use in the primary treatment of domestic wastewater. In most cases, they are used as coagulating and flocculating agents and are derived from seeds, leaves, bark or sap, roots, and fruits of trees and plants. In this research, the use of Cassia fistula seed was evaluated for the removal of turbidity and color in domestic wastewater from a pumping station in the city of Cartagena (Colombia). The optimal dose of C. fistula seed powder was determined by jar test using an E&Q F6-300 digital flocculator. Physicochemical parameters such as turbidity and color were determined, following the recommendations of APHA (Standard Methods for Water and Wastewater), expressing the results in UNT (Total Nephelometric Units) for turbidity, and UPt-Co (Platinum-Cobalt Units) for the color.  The results obtained show that with a dose of 160 mgL-1 of the coagulant extracted from the C. fistula seed, a value of 34.14 NTU is reached for removal of 62.18% with respect to the initial turbidity value. The color decreases reaching a minimum value of 88.59 UPC for removal of 64%, at a dose of 160 mgL-1 of natural coagulant.  The seed C. fistula exhibited good coagulating properties at low doses and can be an important alternative for the removal of color and turbidity in wastewater. Keywords: color, removal, turbidity, water treatment.