Potassium permanganate kmno4

Without further purification, we used all chemical compounds exactly as they were given to us. Graphite powder (<150 $\mathsf{\mu }$ m, 99.9%) (Sigma Aldrich, St. Louis, MO, USA), sulfuric acid (H₂SO₄, ACS reagent, 95.0–98.0%) (Sigma Aldrich), potassium permanganate (KMnO₄, ACS reagent, 99.0%) (Sigma Aldrich), hydrochloric acid (HCl, ACS reagent, 37%) (Sigma Aldrich), citric acid (CA, C₆H₈O₇, ≥99.5%) (Sigma Aldrich), and hydrogen peroxide (H₂O₂, 30%) (Merk, Rahway, NJ, USA).

In the laboratory, graphene and reduced graphene oxide (RGO) were synthesized using an improved Hummer's process. Rhodamine B dye (C₂₈H₃₁ClN₂O₃) (AR Grade, 99%), hydrogen peroxide (H₂O₂) (98%), potassium permanganate (KMnO₄) (AR Grade, 99%), sulfuric acid (H₂SO₄) (98%), Ortho phosphoric acid (o-H₃PO₄) (98%), methanol (98%) and hydrazine hydrate (H₆N₂O) (98%) were purchased from Sigma-Aldrich. The double distilled water was used for this entire study.

Milli-Q water (resistivity 18.2 MΩ cm at 25 °C) was used in all experiments. PTA (99.995%) and potassium permanganate (KMnO₄, >99.0%), sodium citrate, sodium chloride, bis(p-sulfonatophenyl)-phenylphosphine (BSPP, 97%), agarose and tetrachloroauric(III) acid (99%) were purchases from Sigma-Aldrich and used without any further purification. Gasket and O-rings for sealing of the liquid cell, PTFE tubings as well as small and large Poseidon E-chips were obtained directly from Protochips Inc²¹ . All used small E-chips had e-beam-transparent SiN membranes of nominal 550 μm × 20 μm expansion and flow spacers with 150 nm thickness (serial number: EPB-52DNF). As large E-chips, standard EPT-55W were used. RIE etched chips were obtained from Protochips company in the frame of a collaborative project. These modified chips are not catalog products but can be commercially requested from the company as of now. A possible fabrication routine is described in the physical prototyping of diffusion cells section. Two different LP-TEM sample holder setups, Poseidon Select™ and Poseidon 200™ (both Protochips Inc²¹ ), were used for experiments. All glassware was cleaned with aqua regia and rinsed thoroughly with Milli-Q water.

Graphite flakes (catalogue number: 332461), sodium nitrate (NaNO₃) > 99%, sulphuric acid (H₂SO₄) 95.0–98.0%, potassium permanganate (KMnO₄) > 99% and hydrogen peroxide solution (H₂O₂) 30% (w/w) were purchased from Sigma-Aldrich (UK). Phosphate buffered saline (PBS) pH 7.45, tryptic soy agar (Oxoid Ltd. CM0131), and broth (Oxoid Ltd. CM0129) were purchased from Fisher Scientific (UK). Stains SYTO 9 and propidium iodide (PI) were purchased from Thermo Fisher Scientific (UK).

Methyl Methacrylate (MMA) and Glycidyl methacrylate (GMA) were purchased from ACROS (USA), and Potassium persulfate and sodium bisulfite were obtained from Sigma Chem. Co. (St. Louis, MO, USA), Ethanol absolute perused from Adwic, Egypt, and finally, MB from Aldrich, Germany was perused. Potassium dichromate (K₂Cr₂O₇), minimum assay 99%, was supplied by Sigma Aldrich, Germany. Potassium permanganate (KMnO₄), a minimum assay of 99%, was supplied by Sigma Aldrich, Darmstadt, Germany.

Graphite powder (purity 99.9995%), sulphuric acid (H₂SO₄, 95–97%), sodium nitrate (NaNO₃), potassium permanganate (KMnO₄) and KOH were purchased from Sigma-Aldrich. Hydrogen peroxide (H₂O₂, 30%) and hydrochloric acid (HCl, 37%) were purchased from Chem-Supply and Biolab respectively. CO₂ and N₂ gases were supplied by Azeratech Engineering (Pulau Pinang, Malaysia).

Polysulfone (PSF, Udel^® P-3500)—the forming material for hollow fiber membrane—was procured from Solvay. N,N-dimethylacetamide (DMAc) and ethanol obtained from Merck and tetrahydrofuran (THF) obtained from QReC were used as co-solvents for the dope solution preparation. GO nanosheets were self-synthesized in this work using graphite powder supplied by Sigma Aldrich. Other chemicals used to synthesize GO were sulfuric acid (H₂SO₄) (95–97%, Merck, Kenilworth, NJ, USA), sodium nitrate (NaNO₃) (99.5%, Riedel-de Haen, NJ, USA), potassium permanganate (KMnO₄) (99%, Sigma-Aldrich, St. Louis, MO, USA), and hydrogen peroxide (H₂O₂) (30%, Merck). For the process of GO washing, barium chloride 2-hydrate (BaCl₂(H₂O)₂) (99%, Riedel-de Haen), hydrochloric acid (HCl) (37%, Merck), and acetone (>99%, Merck) were used. To prepare a selective coating layer on the outer surface of hollow fiber membrane, Pebax^® MH 1657 in ethanol obtained from Arkema was used. For the gutter layer formation, PDMS coating solution was prepared using a Sylgard^® 184 Silicone Elastomer base and curing agents supplied by Dow Corning. To evaluate the membrane separation performance, four purified gases—i.e., CO₂, CH₄, O₂, and N₂—supplied by Mega Mount Industrial Gases Sdn. Bhd., Malaysia, were used.