A novel advanced oxidation process, combined zero-valent iron and sulfite (Fe⁰/sulfite) system containing oxygen, was firstly developed to efficiently degrade organic pollutants at weak acidic and neutral conditions by selecting X-3B as a target compound. The removal of X-3B was attributed to the formed reactive radicals, such as SO₄ ^-, SO₅ ^- and HO^[rad], in the Fe⁰/sulfite system, and SO₄ ^- was evidenced as the principal reactive species. The quite low removal efficiency of X-3B (less than 5%) after reaction for 90 min with purging nitrogen gas suggests oxygen to be an essential factor for producing SO₄ ^- in the system. Optimal dosages of Fe⁰ and sulfite were suggested to be 0.5 mM and 1.0 mM, respectively, in the system as both the two chemicals would scavenge the reactive radicals at overdosing. The presence of 2 mM bicarbonate significantly inhibited the removal of X-3B from 74.1% to 37.5% in the system. Halide ions inhibited the removal of X-3B following a trend that Cl⁻ <Br⁻ <I⁻. HSO₃ ⁻, being effective in complexion of Fe(II) and transferring Fe(III) to Fe(II), is the main species during pHs 4–6, which results in the good reuse of Fe⁰ and the highest removal efficiency of X-3B at weak acidic condition. Fe⁰/sulfite system was also evidenced to be effective in the treatment of actual textile effluents along with improving biodegradability, and the removal of nitrobenzene, methylparaben, bisphenol A, imipramine and amitriptyline. Overall, this study provided a cheap and easy operational advanced oxidation process in treatment of aqueous organic pollutants.

This installment of Trends &amp; Controversies provides an array of perspectives on the latest research in system informatics. Kang Zhao, Yao Xie, and Kwok-Leung Tsui introduce the work in 'System Informatics: From Methodology to Applications.' On the methodology side, in 'Projection-Based Process Monitoring and Empirical Divergence,' Wenpo Huang, Wei Jiang, Qingming Wei, and Yanting Li propose a framework of projection-based methods, and in 'One-Class Classification Methods for Process Monitoring and Diagnosis,' Sugon Cho and Seoung Bum Kim discuss how a data analytics algorithm can be used as a control chart. On the application side, 'IoT-Enabled System Informatics for Service Decision Making,' by Kaibo Liu and Jianjun Shi, reviews current trends and future opportunities for IoT, with a special focus on issues related to the big data collected by multiple sensors. 'Quantifying the Risk Level of Functional Chips in DRAM Wafers,' by Young-Seon Jeong, Byunghoon Kimb, Seung Hoon Tong, In-Kap Chang, and Myong K. Jeong, not only identifies research challenges and opportunities for decision making with massive data in the process of semiconductor manufacturing but also quantifies the risk level of functional chips in DRAM wafers. Finally, 'Flight Operations Monitoring through Cluster Analysis: A Case Study,' by Florent Charruaud and Lishuai Li, describes a new method called cluster-based anomaly detection to help airline safety experts monitor daily flights and detect anomalies.