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Glyphosate as an effective broad-spectrum herbicide is frequently detected in various water and soil resources. Given the ubiquity of β-MnO 2 and δ-MnO 2 colloids in groundwater and soil, the abiotic removal of glyphosate by MnO 2 colloids was investigated. β-MnO 2 colloids exhibited superior glyphosate removal efficiency, up to 37%, compared to 21% for δ-MnO 2 colloids at a pH of 4.0. Glyphosate removal involved simultaneous adsorption and oxidation process, identified by HRTEM, NH 3 -TPD, XPS, LC-MS, FTIR analyses and the occurrence of aminomethylphosphonic acid (AMPA) and Mn 2+ . Moreover, adsorption dominated the removal of glyphosate by two MnO 2 colloids. The solution pH had a substantial effect on glyphosate removal. Co-existing ions in the solution, such as carbonate (CO 3 2- ), phosphate (Na 2 HPO 4 , NaH 2 PO 4 ) and humic acid (HA), were also found to impede glyphosate removal. Phosphate, in particular, exhibited a strong competitive effect for adsorption sites on both MnO 2 colloids. Of them, the removal of glyphosate by β-MnO 2 colloids was more prone to occur due to its higher specific surface area, abundant oxygen vacancies, and moderate acid sites. However, δ-MnO 2 colloids presented a stronger oxidation capacity than that of β-MnO 2 colloids due to the quicker generation rate of Mn 2+ . Finally, AMPA was the same products by two MnO 2 colloids in the oxidation process, revealing the degradation pathway based on the cleavage of C-N bond. Therefore, by comparing kinetics and mechanisms of glyphosate removal by β- and δ-MnO 2 colloids, this study improves us better understanding for the behavior of glyphosate in the environment., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

This study analyses the electrokinetic (EK) contribution to the removal from a clay soil of a mixture of 10 different contaminants of emerging concern (CECs; 17β-estradiol, E2; sulfamethoxazole, SMX; bisphenol A, BPA; ibuprofen, IBU; 17α-ethinylestradiol, EE2; oxybenzone, OXY; diclofenac, DCF; triclosan, TCS; caffeine, CAF; carbamazepine, CBZ). After 4 days, the CECs natural attenuation was between 0% (CBZ) and 90% (E2) yet increasing with the application of EK (20 mA, 12 h ON/OFF) to 14% (CBZ) and 100% (E2). When EK was applied, the CECs more recalcitrant to biodegradation (i.e. ≤ 13% biotic decay) mostly underwent electro-chemical induced degradation (OXY, DCF, TCS, CAF, CBZ). Daily irrigation enhanced the rates of the electro-oxidation -osmosis and -migration, increasing the CECs decay. After 8 days of EK treatment, the CECs decay increased, surpassing the decay lag phase of some compounds (OXY, TCS, and CBZ). Yet after 16 days, most CECs showed similar removals with and without EK, with EK only acting positively on SMX, OXY, TCS and CBZ (ca. +10%). Our results support that EK application can improve the removal of CECs from soil, however, under the conditions tested, 16-day treatment lead to pH alterations that decreased the bioremediation efficiency and inhibited electro-degradation near the cathode., (Copyright © 2020 Elsevier B.V. All rights reserved.)

Applying manganese(IV)- or iron(III)-(hydr)oxides to remove pharmaceuticals from water could be attractive, due to the capacity of these metal oxides to remove pharmaceuticals and be regenerated. As pharmaceutical removal under anaerobic conditions is foreseen, Mn(IV) or Fe(III) regeneration under anaerobic conditions, or with minimum oxygen dosage, is preferred. In this study, batch experiments are performed to investigate (1) Mn(IV) and Fe(III) regeneration from Mn(II) and Fe(II); (2) the pharmaceutical removal during biological Mn(IV) and Fe(III) regeneration; and (3) anaerobic abiotic pharmaceutical removal with different Mn(IV) or Fe(III) species. Results show that biological re-oxidation of reduced Mn(II) to Mn(IV) occurs under oxygen-limiting conditions. Biological re-oxidation of Fe(II) to Fe(III) is obtained with nitrate under anaerobic conditions. Both bio-regenerated Mn(IV)-oxides and Fe(III)-hydroxides are amorphous. The pharmaceutical removal is insignificant by Mn(II)- or Fe(II)-oxidizing bacteria during regeneration. Finally, pharmaceutical removal is investigated with various Mn(IV) and Fe(III) sources. Anaerobic abiotic removal using Mn(IV) produced from drinking water treatment plants results in 23% metoprolol and 44% propranolol removal, similar to chemically synthesized Mn(IV). In contrast, Fe(III) from drinking water treatment plants outperformed chemically or biologically synthesized Fe(III); Fe (III) from drinking water treatment can remove 31-43% of propranolol via anaerobic abiotic process. In addition, one of the Fe(III)-based sorbents tested, FerroSorp ® RW, can also remove propranolol (20-25%). Biological regeneration of Mn(IV) and Fe(III) from the reduced species Mn(II) and Fe(II) could be more effective in terms of cost and treatment efficiency., (Copyright © 2018 The Authors. Published by Elsevier Ltd.. All rights reserved.)