2.2 Micropollutant adsorption

properties of CDs with the porosity and high surface area of ACs to yield an

micropollutants and under environmentally relevant conditions.

Technology, Science and Culture - A Global Vision, Volume II

centrations (1 μg L<sup>1</sup>

2. Methodology

30

2.1 Micropollutant monitoring

adsorbent with superior adsorption kinetics and an adsorption capacity on the order of AC. However, we have not yet tested our β-CD polymer against diverse groups of

The objectives of this research were twofold. First, we aimed to assess the relative contributions of various sources to micropollutant occurrence in the Hudson River Estuary, a major freshwater system in New York. We collected grab samples at 17 sites along the Hudson River Estuary between the Mohawk River and the Tappan Zee Bridge. Samples were collected in May, July, and September of 2016. A map of the 17 sampling sites is provided in Figure 2 along with a delineation of the watersheds for each of the tributaries. The sites include three sewage treatment plant outfalls, five sites at the mouth of tributaries of the Hudson River, seven

sites inside the tributaries of the Hudson River, and two control sites in the midchannel of the Hudson River at the northern and southern ends of the study boundaries. The samples were analyzed using a target screening analysis to quantify the occurrence of up to 200 micropollutants commonly identified in surface waters around the world. Second, we aimed to evaluate the performance of porous β-CD polymers (P-CDPs) as adsorbents of micropollutants in aquatic matrices. Adsorption kinetics and micropollutant removal were measured in batch and flow-through experiments for a mixture of 90 micropollutants at environmentally relevant con-

(NOM). The performance was benchmarked against a coconut shell activated carbon (CCAC). Data reveal slower and nonselective uptake on CCAC and faster and selective uptake on P-CDP. The presence of NOM had a negative effect on the adsorption of micropollutants to CCAC but had almost no effect on adsorption of micropollutants to P-CDP. These data highlight advantages of P-CDP adsorbents relevant to micropollutant removal during water and wastewater treatment.

All spatial analyses and mapping were conducted with ArcMap 10.4. All of the data used is freely available online including the digital elevation models used to delineate the Hudson River Estuary catchment area and tributary watersheds, land cover data, and industrial discharge sites including wastewater treatment plants, hospitals, and population data. Grab samples were collected in 1 L amber, trace clean glass bottles. The samples were shipped in a cooler to our laboratory at Cornell University at the end of each sampling campaign. Samples were stored at 4°C and in the dark until sample preparation within 24 h of arrival in our laboratory. We used a mixed-bed solid-phase extraction (SPE) method to concentrate the 1 L samples as previously described [7, 30]. The high-performance liquid chromatography and tandem mass spectrometry (HPLC-MS/MS) method was previously developed and validated for a broad range of micropollutants [30, 31]. A target screening approach was used to quantify the concentrations of 200 micropollutants in each of the samples. Detection limits are generally in the low ng L<sup>1</sup> range for the

micropollutants on this list. Statistical analyses were conducted using R Statistical Software and an alpha level of 0.01 was used to determine significance. The hclust function was used to cluster micropollutants using Ward's method based on the occurrence profiles for all the detected micropollutants at each sample site during each sampling event. Paired Wilcoxon rank-sum tests were used to assess the differences between micropollutant concentration profiles across sample sites.

) and in the presence and absence of natural organic matter

P-CDP was synthesized as previously described [25], and the CCAC is commercially available (AquaCarb 1230C, Westates Carbon, Siemens, Roseville, MN). To increase the similarity in particle size between the P-CDP and CCAC, the CCAC was pulverized with a mortar and pestle until >95% (mass) passed a 74 μm sieve (200 US mesh). The P-CDP and the pulverized CCAC were dried under a vacuum in a desiccator for 1 week and stored in a refrigerator at 4°C. We selected 90 micropollutants based on their environmental relevance and previous reports of their adsorption onto AC. Stock solutions of each compound were prepared at a concentration of 1 g L<sup>1</sup> using 100% HPLC-grade methanol. The stock solutions were used to prepare an analytical mix containing all 90 micropollutants at a concentration of 10 mg L<sup>1</sup> using nanopure water.

## 2.3 Batch experiments

Batch experiments were performed in 125 mL glass Erlenmeyer flasks with magnetic stir bars on a multi-position stirrer (VWR) with a stirring rate of 400 revolutions per minute (rpm) at 23°C. Batch experiments were performed at an adsorbent dose of 10 mg L<sup>1</sup> . The micropollutants were spiked to generate an initial concentration of each adsorbate of 1 μg L<sup>1</sup> . Samples were collected in 8 mL volumes at predetermined sampling times (0, 0.05, 0.17, 0.5, 1, 5, 10, 30, 60, 90, 120 min) and filtered through a 0.22 μm PVDF syringe filter (Restek). Control experiments to account for other micropollutant losses were performed under the same conditions with no addition of adsorbent. All samples were analyzed by means of HPLC-MS/MS to determine the aqueous phase concentration of each micropollutant as a function of contact time with the adsorbent.

### 2.4 Flow-through experiments

Flow-through experiments were performed with a 10 mL Luer Lock glass syringe and Restek 0.22 μm PVDF syringe filters at 23°C with a constant flow rate of 25 mL min<sup>1</sup> . Flow-through experiments were performed with either nanopure water or nanopure water amended with humic acid (HA) as a surrogate for NOM and NaCl as a surrogate for inorganic matrix constituents. Syringe filters were loaded with adsorbent by passing 1 mL of the adsorbent suspension through the inorganic syringe filter to form a thin layer of 1 mg of adsorbent on the filter surface. Following the loading of the filters with adsorbent, 8 mL of the analytical mix (1 μg L<sup>1</sup> ) was pushed through the adsorbent-loaded filter with constant pressure over 20 s. Control experiments were performed in the same way with no adsorbent on the filter to account for losses through the filter. The filtrates were analyzed by means of HPLC-MS/MS to determine the aqueous phase concentration of each micropollutant.
