Biochars-FexPCu hybrides deriving from solid waste and waste acids for elimination of refractory organic pollutants from pharmaceutical wastewater

•Composites of biochars-FexPCu are derived from solid waste, waste acids and iron ores.•Tetrachloropicolinic acid is removed at pH 4–10 and 25–65 °C in the salinity range of 0–25 g/L.•The coexisting •OH, O2•-, 1O2 and electrons leads to mineralization of TCPA.•BC-FexPCu efficiently pretreats wastewater from a pharmaceutical plant.•BC-FexPCu has great potential to be cost-efficient water purification materials.