High-performance arsenic removal from natural waters using a coiled flow inverter

Arsenic remains a contaminant of emerging interest in water pollution due to its significant threat to public health, removal of which is still challenging problem. To develop miniaturized, low-cost, sustainable and high-performing water purification systems for continuous removal of arsenic, this study leverages the advantages of enhanced radial mixing of coiled flow inverter (CFI) reactor. A comprehensive evaluation of CFI adsorptive removal of As(V) from natural waters using MgO nanoparticles was conducted to determine the impact of key parameters such as flowrates (10 mL/min, 135 mL/min), initial pollutant concentration (1-200 ppm As(V)), adsorbent dosage (0.2-2 mg/mL), pH (2-10) and competing ions (phosphate, sulphate, chloride and carbonate). Findings showed experimental adsorption capacity of 184 mg/g and 98% adsorption efficiency for As(V) were achieved within 38 seconds at a flow rate of 135 mL/min, initial As(V) concentration of 10 mg/L and adsorbent dosage of 1.5 mg/mL. To demonstrate its practical application, studies performed on selectivity in the presence of co-ions (phosphate, sulphate, chloride and carbonate), water matrix using real water (Torrens River water) showing good selectivity (72-78%) and recycling (99% after 5 cycles) potential. Benchmarking experiments in batch and CFI reactor verified that outstanding removal efficiency (98%) can be attained in 38 seconds at 135 mL/min flow rate in a CFI reactor compared to 24 hrs in a batch reactor, demonstrating the efficacy of the miniaturized compact device based on CFI as a new-generation practical water purification technology. • Coiled flow inverter as a compact microreactor for advanced adsorption • Improved mixing with lower cost, time and footprint via coiled flow inverter • Ultrafast arsenic removal (98%) in 38 seconds via CFI, outperforming batch process • High arsenic removal (> 98%) at 0.5 and 1 ppm As (V) using river water sample Remarkable regeneration efficiency via coiled flow inverter (> 90%) after 5 cycles