Ph meter

Following blood collection, rumen fluid was collected after 3 h of feeding using the oral stomach tube method, as described by Shen et al [22 (link)]. Rumen fluid pH was measured immediately using a pH meter (Ohaus Corp., Parsippany, NJ, USA). The 1 mL VFA rumen fluid samples were mixed with 0.2 mL of 25% meta-phosphoric acid and storage at −20°C until analysis. An additional 30 mL of rumen fluid was stored at −20°C for ruminal ammonia nitrogen (NH₃-N) analysis. NH₃-N concentrations were determined using a modified colorimetric method [23 (link)]. The VFA concentrations were determined using an Agilent Tech 7890A gas chromatograph (Hewlett Packard, Waldbronn, Germany) with a Supelco fused silica capillary column (30 m×0.25 mm×0.25 μm).

The adsorbents were characterized in terms of point of zero charge $p{H}_{PZC}$ . To this aim, 20 mL of distilled water at neutral pH was added to 12 Erlenmeyer flasks of 50 mL. Then, the pH of the 12 solutions was adjusted with either HCl (0.1 M) or NaOH (0.1 M). After that, 20 mg of the adsorbent powder was added to all the solutions. Each suspension was stirred for 24 h, and the final pH values were measured using a pH meter (OHAUS). The final pH minus the initial pH value, as a function of the initial pH values, was plotted to obtain pH_PZC. The pH_PZC is calculated as the terminal pH value corresponding to the intersection of the obtained curve with the abscissa axis.
The infrared spectra of the adsorbents before and after modification and the PEG-SG were recorded by an FTIR spectrophotometer (Shimadzu) in the range of 4500–500 cm⁻¹.

Reducing sugar was determined by the dinitrosalicylic acid (DNS) method using glucose (0–1000 µg/mL) as a standard as described by Miller [30 (link)] with slight modifications.
Total soluble solid (°Brix) was measured by a portable refractometer (Trans Instruments, Singapore). The pH was measured by a pH meter (OHAUS^®, Parsippany, NJ, USA).

The sampling sites are located at alpine lakes in the Hengduan Mountains (27°31′40″–28°14′31.2″N and 98°12′49.2″–100°4′1.2″E), which are under the conditions of low temperature and hypoxia throughout the year. A total of 15 alpine lake sediment samples were collected using a stainless steel grab sampler at different locations in the Hengduan Mountains in 2015 (Figure 1). GS2‐1, GS2‐2, GS3‐1, GS3‐2, GS3‐3, GS4‐2, and GS4‐3 were collected in October or November; while DK, DV, GGC, NB, NB‐1, SL, WD‐2, and ZN were acquired in May or June. Samples (upper 3 cm) from each station were pooled, homogenized, collected in sterile 50 ml tubes, and immediately stored at −20°C until DNA extraction was undertaken in our laboratory. We classified the sample number based on the sampling order. At each station, depth and sediment temperature (T) were profiled by a SeaBird CTD (SBE37 MicroCAT, SeaBird), and altitude was determined by GPS. The pH was detected using a pH meter (Ohaus, NJ), and dissolved oxygen (DO) was measured by a DO meter (HQ30D, HACH). Sediment water content (SWC) (10 g of each sample) was determined as gravimetric weight loss after drying the sediment at 105°C until constant weight (Guo et al., 2015).

In order to investigate the concentration of impurities in PG and backfill samples, the toxicity leaching test was conducted according to HJ 557-2010. After curing for 28d, the backfill samples were grounded and sieved through a 3.0 mm screen. The powders were mixed with deionized water in a container at a mass proportion of 1:10 and shaken at 110 rpm/min on a rotary shaker for 8 h. Then the mixtures were placed on the table for 16 h. Finally, the mixtures were filtered through a 0.45 mm filter, and the leachates were collected for further analysis.
The pH value of PG, bleeding water and the leachate of toxicity leaching test was measured by pH meter (Ohaus, US). The concentrations of SO₄²⁻ and PO₄³⁻ were determined by ammonium molybdate tetrahydrate spectrophotometry (Shimadzu, Japan). The total dissolved solids (TDS) and the concentration of F⁻ were measured by TDS meter (Ohaus, US) and fluorine ion-selective electrode (Leici, China), respectively.

Average FW was determined using a Mettler Toledo analytical balance after berries had been sorted, washed, and dried. An aliquot of 1 g of fresh grape homogenate was centrifuged for 5 min at 1200× g, and TSS (°Brix) and pH of the supernatant were measured using a bench-top refractometer (Hanna Instruments, Woonsocket, RI, USA) and pH meter (OHAUS, Parsippany, NJ, USA).