P-Toluene sulfonic acid and H2O2 synergistically strengthen terpinolene for efficient decapsulation of waste crystalline silicon photovoltaic laminates

Decapsulation is the first step of recycling waste crystalline silicon photovoltaic (PV) panels. Nowadays, wet decapsulation has been a mainstream decapsulation method. It delivers high-purity decapsulation products and enables full-component recycling of laminates. However, current wet decapsulation technologies suffer from several limitations, including excessively high solvent concentrations and significant environmental risks. Moreover, critical issues such as ineffective decapsulation at low solvent concentrations, undefined waste liquid treatment methods, and uncontrollable decapsulation effect remain to be resolved. In order to solve these problems, this study used p-toluene sulfonic acid (PTSA) and hydrogen peroxide (H 2 O 2 ) to strengthen terpinolene efficiently decapsulating waste crystalline silicon PV laminates. PTSA and H₂O₂ were shown to strengthen terpinolene's decapsulation efficiency, achieving 100 % decapsulation rates even at low terpinolene concentrations. A positive correlation was observed between terpinolene concentration and the degree of silicon layer fragmentation. This paper analyzed the characteristics of the decapsulated waste liquid, such as high calorific value and low metal dissolution capacity. The feasibility of waste liquid combustion treatment was evaluated for the first time from the perspective of environmental impact. Meanwhile, the mechanism by which auxiliary reagents (PTSA and H 2 O 2 ) work in synergy to strengthen the decapsulation of terpinolene was deeply analyzed: PTSA provided acidic conditions, and H 2 O 2 act as a free radical initiator. The two worked together to activate terpinolene to generate more terpinolene free radicals (Terp·). Terp· attacked the main chain and bridging of ethylene-vinyl acetate polymer (EVA), leading to chain breaks and the decapsulation effect. This research provides a theoretical basis for the wet decapsulation of waste crystalline silicon PV laminates, links laboratory innovation with practical application, and offers a sustainable approach for industrial-scale PV recycling. Synopsis The synergistic effect of PTSA and H 2 O 2 strengthens the terpinolene to completely decapsulate the waste crystalline silicon photovoltaic laminates.