Whatman gf f

Never-dried softwood kraft pulp fibers (Metsä Board Husum mill, Sweden) were used to prepare TCNF following the method of (Saito et al. 2007 (link)). Sulfur-free birch lignin produced by BLN process (named after the company that initially developed the technology) was provided by CH Bioforce Oy (Finland). Briefly, the process involves hot water (150 °C) extraction of hemicelluloses from biomass followed by alkali cooking to extract lignin, all in oxygen-starved conditions (von Schoultz 2015 ). The LNPs were prepared by anti-solvent nanoprecipitation in acetone and water (Figueiredo et al. 2021 (link)). These LNPS were cationized by coating with glycidyltrimethylammonium chloride (GTAC)-treated lignin to produce cationic LNPs (cLNPs) (Agustin et al. 2022 (link); Sipponen et al. 2017 (link)). The detailed preparation of TCNF, LNPs, and cLNPs and their basic characteristics are available in the Supporting Information (Fig. S2). Hexadecane, GTAC, cyclohexanone, and acetone were purchased from Fisher Scientific (Finland). The pharmaceutical compounds, which are certified reference materials, dialysis membrane tubing (Spectra/Por 7, 6–8 kDa molecular weight cut-off (MWCO), Spectra/Por 1, 1 kDa MWCO), glass microfibre filters with a 0.7 µm pore size (Whatman GF/F), chromasolv-grade acetonitrile and methanol were obtained from Sigma-Aldrich (Finland).

Microalgae dry weight concentration C_x was measured gravimetrically by filtering given culture volume through a pre-dried and pre-weighed glass-fiber filter (Whatman GF/F, 0.47 μm pore size, VWR, France). The filters were dried at 105 °C for at least 24 h and then reweighed after being cooled in a desiccator for 10–15 min. The samples were analyzed in triplicates and the reported biomass concentration corresponded to the mean value.

The temperature, turbidity, dissolved oxygen, salinity, and pH of surface seawater were recorded in situ with a YSI EXO² Multiparameter Sonde (YSI Inc., Yellow Springs, OH, USA) at a depth of 50 cm. For the analyses of nutrient content, samples were filtered through glass-fiber filters (Whatman GF/F, 47 mm, 0.68 µm), fixed with chloroform, and then stored at −20 °C. The concentrations of nutrients were analyzed using a continuous flow analyzer (Skalar San++, the Netherlands). For the Chl a measurement, 100 mL of seawater was filtered using Whatman GF/F filters after initial filtration through a 200 µm nylon sieve. The filter membrane was wrapped in aluminum foil and stored in a dark environment at −20 °C prior to spectrophotometric analysis. In addition, the samples were fixed with paraformaldehyde (final concentration of 1%) and stored in a freezer at −80 °C before bacterial density determination. After SYBR Green I (1:10,000, V/V) staining was performed in the dark for 15 min, the bacterial concentration was determined by flow cytometry (FACS Calibur, BD, Franklin Lakes, NJ, USA) [22 (link)].

Water samples were filtered through a pre-combusted (500°C for 6 h) filter (GF/F Whatman^™), and stored frozen until analysis for nutrient concentrations at the University of Hawai‘i at Hilo Analytical Laboratory. Nutrients were analyzed on a Pulse Technicon^™ II autoanalyzer using standard methods (NO₃^- + NO₂^- [Detection Limit (DL) 0.07 μmol/L, USEPA 353.4], total dissolved phosphorus (TDP) [DL 0.5 μmol/L, USGS I-4650-03], H4SiO4 [DL 1 μmol/L, USEPA 366]), and reference materials (NIST; HACH 307–49, 153–49, 14242–32, 194–49). Total dissolved nitrogen (TDN) was analyzed by high-temperature combustion, followed by chemiluminescent detection of nitric oxide (DL 5 μmol/L, ASTM D5176, Shimadzu TOC-V, TNM-1) [58 ]. Salinity, pH, and temperature were measured at the time of water collection using a YSI Pro 2030 multi-parameter probe.

Hospital wastewater samples (n = 11), including five influents (IN) and six effluents (EF), were collected from six different hospital treatment stations in North Vietnam, Lang Son (LS_EF) and Hanoi (ND_IN, ND_EF, RHM_EF), and South Vietnam, Can Tho (CT_IN) and Ho Chi Minh City (NHD1_IN, NHD2_IN, NHD3_IN, NHD_EF, CR1_EF, CR2_EF), according to US EPA 1694 guideline with some modifications. All samples were collected and kept in plastic bottles (1 L) prerinsed with ultrapure water in the laboratory and rinsed with sample on the sampling site. The samples were kept at 4°C using glaciers and ice bag and brought directly to the laboratory on the day of sampled collection or kept at −20°C and brought back to the laboratory on another day. In laboratory, samples were filtered by using microglass fiber filters (GF/F Whatman, ϕ ≤ 0.7 µm) helped by vacuum filtration unit to eliminate suspended matters. The prefilter (GF/A Whatman, ϕ ≥ 1.6 µm) was used if the samples have greatly been charged by suspended matters. All glass microfiber filters have been treated by baking at 450°C for 4 h in order to eliminate all organic contaminants. The filtered samples were stored in −20°C and then either extracted and analyzed within 48 h after collection or kept at −80°C until analysis.