Recently, calcium sulfite (CaSO₃) has been increasingly considered to be the most potential substitute for PMS/PDS to produce SO₄·⁻ for degrading target organic pollutants due to its fewer toxic side effects, lower cost, and absence of residues after decontamination. In this regard, herein, we report carbon nanotubes (CNTs) as an efficient catalyst and nanoreactor for activating CaSO₃ for water decontamination. Compared with NaHSO₃ and Na₂SO₃, the result exhibited that the order of tetracycline (TC) removal rate at 30 min as follow: CaSO₃ (80.2%) > Na₂SO₃(49.3%) > NaHSO₃ (48.8%). Because CaSO₃ can slowly discharge SO₃²⁻, it could be used as a sustained-release SO₃²⁻ source, which could effectively solve the quenching issue of SO₄·⁻ at a high concentration of SO₃²⁻. Control experiments confirmed the vital roles of electron transfer and dissolved O₂ in the formation of SO₃·⁻ and SO₄·⁻ in the CNTs/CaSO₃ system, as also verified by quenching experiments and EPR analysis. More importantly, we found that the CNTs/CaSO₃ system had excellent potential for the treatment of actual pharmaceutical wastewater, with the total organic carbon and chemical oxygen demand dropping by 42% and 70% after treatment, respectively. In addition, germination experiments of wheat seeds confirmed that the biotoxicity of TC to wheat seeds was greatly reduced after treatment with the CNTs/CaSO₃ system.

中文翻译：

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碳纳米管作为纳米催化剂和纳米反应器，通过 CaSO3 活化有效处理制药废水

近年来，亚硫酸钙(CaSO ₃ )因其毒副作用小、成本较低、去污后无残留等优点，越来越被认为是PMS/PDS最有潜力的替代品，产生SO ₄ · ⁻来降解目标有机污染物。 。在这方面，我们在此报道碳纳米管（CNT）作为一种有效的催化剂和纳米反应器，用于活化CaSO ₃以进行水净化。与NaHSO ₃和Na ₂ SO ₃相比，30 min时四环素(TC)去除率大小顺序为：CaSO ₃ (80.2%) > Na ₂ SO ₃ (49.3%) > NaHSO ₃ (48.8%) ）。由于CaSO ₃能缓慢释放SO ₃ ²⁻，因此可作为缓释SO ₃ ²⁻源，有效解决高浓度SO ₃ ^2−下SO ₄ · ⁻的猝灭问题。对照实验证实了电子转移和溶解的O ₂在CNT/CaSO _{3体系中SO 3} · ^-和SO ₄ · ^-形成中的重要作用，这也通过淬火实验和EPR分析得到了证实。更重要的是，我们发现CNTs/CaSO ₃系统在处理实际制药废水方面具有良好的潜力，处理后总有机碳和化学需氧量分别下降42%和70%。此外，小麦种子的发芽实验证实，经过CNTs/CaSO ₃体系处理后，TC对小麦种子的生物毒性大大降低。