Mini 2 analyzer

Adsorption Isotherms for CO₂. Ultra-pure grade (99.9995%) CO₂ gas was purchased from PRAXAIR. CO₂ adsorption isotherms at 196 K and up to 1 bar were carried out on a Belsorp mini II analyzer under high vacuum.
Water-loading within Mg-CUK-1. H₂O vapor loadings were performed by a dynamic method, using air gas as the carrier gas, and by using a DVS Advantage 1 instrument from Surface Measurement Systems (mass sensitivity: 0.1 mg, relative humidity (RH), accuracy: 0.5% RH, vapor pressure accuracy: 0.7% P/P₀). Mg-CUK-1 samples were activated at 100 °C for 1 h under flowing dry N₂. The water contents within Mg-CUK-1 analyzed were 25% RH, 22% RH, 20% RH and 18% RH.
Powder X-ray diffraction patterns were collected on a Rigaku Diffractometer, Ultima IV, with a Cu-Kα1 radiation (λ = 1.5406 Å) using a nickel filter. These were obtained from 5° to 50° in 2θ, with 0.02° steps at a 0.08° min⁻¹ scan rate. Profile refinements were performed based on the previously reported Mg-CUK-1-hydrated structure data using the FullProf program (structure NUDLIJ from CCDC database) [14 (link),15 ].

The N₂ adsorption/desorption behavior of hydrochars were determined at 77 K using Belsorp mini II analyzer. The adsorbents were degassed in vacuum at 110 °C and kept overnight followed by further analysis^{28 (link)}. Smartsorb 92/93 surface area analyzer was used to assess the BET surface area of hydrochars. FTIR (Shimadzu’s 8400S model) was used to detect the molecular functionalities prevailing in the hydrochar at 400–4000 cm⁻¹ wavenumber range^{29 (link)}. Horiba Scientific Nanopartica SZ-100 particle size analyzer was used to analyze the zeta potential of hydrochars³⁰ . FEI—Quanta 250 Scanning Electron Microscope (SEM) was used to examine the structural morphologies of hydrochars at a voltage of 8 kV with × 10,000 magnification. FEI—Quanta 250 Transmission Electron Microscope (TEM) was used to interpret the hydrochar’s internal morphologies at an operating voltage 120 kV³¹ . The point of zero charge (pH_zpc) was determined using pH drift method.