Jem 2010fx

The morphology and structure of the adsorbents were recorded using a scanning electron microscope (SEM, S-3400N II, Hitachi, Tokyo, Japan) and transmission electron microscope (TEM, JEM-2010FX, JEOL, Tokyo, Japan). The specific surface area (SSA) and pore size distribution of the C-Cu and AES biochar were determined via N₂ adsorption/desorption with a surface area and pore size analyzer (ASAP 2420, Micromeritics, Norcross, GA, USA). The specific surface areas were calculated from the Brunauer– Emmett–Teller (BET) equation. The total pore volumes were estimated using the adsorbed N₂ amount at the relative pressure P/P₀ of 0.99, and the micropore volumes were calculated from the t-plot method. The pore size distribution was obtained based on the Barrett–Joyner–Halenda (BJH) method. X-ray diffraction (XRD) data for the Cu₂O, AEC biochar, and Cu-C were collected using an X-ray diffractometer (D/max2550PC, Rigaku, Tokyo, Japan) at a scanning speed of 5° 2θ/min over a range of 10° to 100°. The zeta potentials of the C-Cu, AES biochar, and Cu₂O were determined at different pH values using a Zetasizer (Nano ZS-90) from Malvern Instruments, Malvern, UK.

All chemicals including Pluronic triblock copolymers (CAS 9003-11-6) with the number average molecular weights (M_ns) of ∼1100 (product name Pluronic L-31), ∼2900 (Pluronic L-64), ∼5800 (Pluronic P-123), and ∼14 600 (Pluronic F-108) were purchased from Sigma-Aldrich. Aqueous CTAB solution (0.2 M) was recrystallized twice. X-ray diffraction (XRD) patterns were obtained with Rigaku Ultima IV diffractometer using CuKα radiation (λ = 1.54056 Å) in θ–θ mode. JAC ultrasonic 1505 (150 W, 40 kHz) was used for sonication. Transmission electron microscopy (TEM) images were obtained with JEOL JEM 2010FX operating at 200 kV. Scanning electron microscopy (SEM) images were taken with JEOL JSM 6700F with an operating voltage of 5.0 kV. Fourier transform infrared (FTIR) spectra were recorded with JASCO FTIR-4600 type A, ranging from 650 cm⁻¹ to 4000 cm⁻¹ with a resolution of 4 cm⁻¹ and with an average scan of 8. Without adding KBr or making KBr pellets, sample was placed on the single-reflection ATR accessory and the spectra were measured while the pressure applicator was implemented.