<p>The protection of existing water resources and the reuse of treated wastewater have become increasingly important for environmental sustainability and human health. Among the pollutants in wastewater, phosphorus is one of the major contributors to eutrophication and cyanobacterial growth. Natural adsorbents are widely used for phosphorus removal because of their low cost and simple application. When selecting the most suitable adsorbent, factors such as physicochemical properties, phosphorus adsorption capacity, cost, and availability should be considered. In this study, the phosphorus removal performances of bentonite clay, thermally modified bentonite, Lefke stone, thermally modified Lefke stone, and biochar derived from Tree of Heaven <i>(Ailanthus altissima</i>) were investigated in synthetic wastewater under different initial pH, adsorbent dose, and phosphorus concentration conditions. The obtained results showed that modified Lefke stone exhibited the highest phosphorus removal performance, achieving up to 100% removal efficiency at the 2% and 5% doses(w/v) under all pH conditions. Although its removal efficiency was high, its adsorption capacity remained lower than that of the chemical treatment because higher adsorbent dosages were required. Thermally modified bentonite achieved up to 54.96% phosphorus removal at the 5% dose, while biochar reached 42.95% removal efficiency under acidic conditions at the 0.2% dose. However, performance of biochar decreased at higher pH levels and phosphorus concentrations, and phosphorus release was observed in some applications. Overall, the results demonstrated that thermally modified Lefke stone is a promising locally available adsorbent for phosphorus removal. Furthermore, the investigated natural materials may provide economical and environmentally friendly alternatives for wastewater treatment applications.</p>