Performance of Annona muricata (Soursop) and Persea americana (Avocado pear) Leaves as Natural coagulants in water treatment

The increasing demand for sustainable and environmentally benign water treatment technologies has stimulated interest in plant-based natural coagulants as alternatives to conventional chemical coagulants. This study evaluated the performance of Annona muricata (soursop) and Persea americana (avocado pear) leaf extracts as natural coagulants for improving water quality. Dried leaf powders were prepared and applied at different dosages (0.1–0.4 g) to raw surface water samples. Physicochemical parameters including turbidity, pH, total dissolved solids (TDS), total hardness, electrical conductivity (EC), salinity, temperature, total suspended solids (TSS), and total solids (TS) were determined using standard analytical methods. Heavy metals (Cr, Cu, and Fe) were analyzed using Spectrophotometer (HACH Dr 1900). The results demonstrated notable contaminant removal, particularly at lower dosages (0.1–0.2 g). Turbidity reduction reached approximately 56% (from 2.59 ± 0.02–5.90 ± 0.01 NTU), while color removal efficiency was about 56% (from 7.76 ± 0.05–17.70 ± 0.03 TCU). Significant heavy metal removal was also observed, with chromium reduced by up to 87.5%, copper by 97.6%, and iron achieving complete removal (≈ 100%) under optimal conditions. pH values remained within the WHO recommended range (6.5 ± 0.02–8.5 ± 0.02), indicating minimal alteration of water chemistry. Both plant extracts demonstrated effective coagulation performance, comparable with reported efficiencies of established natural coagulants. The results from this study revealed that A. muricata and P. americana leaves are promising, low-cost, biodegradable coagulants suitable for sustainable water treatment applications.