Pharmaceuticals are discharged into the environment through a variety of pharmaceutical industries, agriculture industries, healthcare facilities and households, resulting in significant environmental and health risks as well as ecological disruptions. While numerous studies have explored the removal of pharmaceuticals like tetracycline (TC) from water-based solutions, there is a need for a thorough investigation into the economic viability and the relationship between TC wastewater treatment and sustainable development goals (SDGs) achievement. Therefore, this work illustrates the preparation of an adsorbent from waste high density polyethylene plastics (HDPE) to remove TC from aqueous solutions, presenting an environmentally friendly treatment approach. The Box-Behnken statistical design was utilized to determine the effects of four process parameters, i.e. absorbent dosage, pH, initial TC concentration and contact time on TC removal efficiency. It was found that HDPE Char (HC) exhibited a superior capability to adsorb TC achieving a removal efficiency of 67.40 ± 2.0%, under a contact time = 60.36 min, adsorbent dosage = 30 mg/L, initial concentration = 6.09 mg/L and pH of 3.28. A quadratic model was formulated to predict the TC removal efficiency, achieving a coefficient of determination of R2 of 0.9768 and adjusted R2 = 0.9535. Moreover, the treatment cost of wastewater containing TC using the proposed adsorption process reached $6.19/m3. The study outputs comply with the sustainability concept through providing a proper adsorbent material to treat wastewater laden with TC (SDG#6), further protecting the aquatic environment (SDG#14) and terrestrial ecosystem (SDG#15).