Removal of organic micropollutants in a drinking water treatment plant by powdered activated carbon followed by rapid sand filtration

Ebrahimzadeh, Salma; Wols, B.A.; Azzellino, Arianna; Kramer, Franca; Hoek, Jan Peter van der

doi:10.1016/j.jwpe.2022.102792

Cited by 5 publications

(1 citation statement)

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“…On the other hand, the surface of Norit CA1, having the lowest pH pzc value of 2.53 (pH ≫ pH pzc ), would be strongly negatively charged. The strong O–H stretching of 2986.9 cm –1 belonging to carboxyl groups and strong C–O stretching of 1065.8 cm –1 belonging to primary alcohols might be responsible for the negatively charged surface of Norit CA1. , The amount of total surface acidic and basic groups identified by the Boehm method also supported this phenomenon that having higher acidic groups resulted in lower pH pzc values …”

Section: Resultsmentioning

confidence: 76%

Impact of Natural Organic Matter Competition on the Adsorptive Removal of Acetochlor and Metolachlor from Low-Specific UV Absorbance Surface Waters

Yilmaz,

Altiparmak,

Dadaser-Celik

et al. 2023

ACS Omega

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Although activated carbon adsorption is a very promising process for the removal of organic compounds from surface waters, the removal performance for nonionic pesticides could be adversely affected by co-occurring natural organic matter. Natural organic matter can compete with pesticides during the adsorption process, and the size of natural organic matter affects the removal of pesticides, as low-molecular-weight organics directly compete for adsorbent sites with pesticides. This study aims to investigate the competitive impact of low-molecular-weight organics on the adsorptive removal of acetochlor and metolachlor by four commercial powdered activated carbons. The adsorption features of selected powdered activated carbons were evaluated in surface water samples collected from the influent stream of the filtration process having 2.75 mg/L organic matter and 0.87 L/mg-m specific UV absorbance. The adsorption kinetics and capacities were examined by employing pseudo-first-order, pseudo-second-order, and intraparticle diffusion kinetic models and modified Freundlich and Langmuir isotherm models to the experimental data. The competitive removal of acetochlor and metolachlor in the presence of natural organic matter was evaluated for varied powdered activated carbon dosages on the basis of UV and specific UV absorbance values of adsorbed organic matter. The adsorption data were well represented by the modified Freundlich isotherm, as well as pseudo-second-order kinetics. The maximum organic matter adsorption capacities of the modified Freundlich isotherm were observed to be 120.6 and 127.2 mg/g by Norit SX Ultra and 99.5 and 100.6 mg/g by AC Puriss for acetochlor-and metolachlorcontaining water samples, respectively. Among the four powdered activated carbons, Norit SX Ultra and AC Puriss provided the highest natural organic matter removal performances with 76 and 72% and 71 and 65% for acetochlor-and metolachlor-containing samples, respectively. Similarly, Norit SX Ultra and AC Puriss were very effective for adsorbing aromatic organics with higher than 80% specific UV absorbance removal efficiency. Metolachlor was almost completely removed by higher than 98% by Norit SX Ultra, Norit SX F Cat, and AC Puriss, even at low adsorbent dosages. However, an adsorbent dose of 100 mg/L and above should be added for all powdered activated carbons, except for Norit SX F Cat, for achieving an acetochlor removal performance of higher than 98%. The competition between low-molecular-weight organics (low-specific UV absorbance) and acetochlor and metolachlor was more apparent at low adsorbent dosages (10−75 mg/L).

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Section: Resultsmentioning

confidence: 76%