Adsorption Equilibrium and Thermodynamics Behavior of Sodium Pentachlorophenol to Biomass-Derived Biochars at Two Pyrolytic Temperatures

Wheat straws were pyrolyzed at two temperatures (200 and 400°C). For two biochar, the Scanning electron microscope (SEM) and the BET surface area were analyzed. The thermodynamics of sodium pentachlorophenate adsorption on biochar were examined. Adsorption isotherm of sodium pentachlorophenate on biochar was determined and correlated with two well-known isotherm equations (Langmuir and Freundlich adsorption isotherm equation). The equilibrium data for sodium pentachlorophenate adsorption were fitted well with the Freundlich adsorption model. The thermodynamic parameters of Gibbs free energy (△Gθ), enthalpy (△Hθ), and entropy (△Sθ) were also calculated, and the positive value of △Hθsuggests the endothermic nature of the adsorption, whereas the negative values of △Gθtend (s) to prove the spontaneous nature of the adsorption process.

Polychlorinated dibenzo-p-dioxins (PCDDs), polychlorinated dibenzofurans (PCDFs) and pentachlorophenol (PCP) in bottom sediments of the Port of Gdansk

Combustion processes are considered to be the main source of the dioxin emission in the Baltic region. Pentachlorophenol (PCP) and its derivatives, pentachlorophenyl laurate (PCPL) and sodium pentachlorophenate (NaPCP) are known as precursors of dioxins. The research was conducted to obtain the first data on the concentration of PCDD/Fs and PCP in the bottom sediments of the Port of Gdansk. Toxicity (the Microtox® test) as well as several sediment parameters have been examined.In the surface layer of bottom sediments from the Port of Gdansk, all congeners of PCDD/Fs have been detected using GC-MS/MS. The highest concentration was obtained for OCDD (224.0–271.0 pg g−1 d.w.) and HpCDD (51.0–36.0 pg g−1 d.w.). The content of ΣPCDDs prevailed over ΣPCDFs. This may indicate that anthropogenic pollution from the land-based thermal sources has the strongest impact on the concentration of dioxins in the port sediments. The concentration of 17 dioxin congeners (WHO-TEQ) did not exceed the probable effect level (PEL) of 21.5 pg TEQ g−1 d.w. The concentration of PCP ranged from bellow the LOD (< 0.85 ng g−1 d.w.) to 12.4 ng g−1 d.w.The positive correlation between toxicity and physico-chemical properties of the analyzed bottom sediments confirms that these parameters are important in terms of environment contamination.

Oxygen vacancy induced selective silver deposition on the {001} facets of BiOCl single-crystalline nanosheets for enhanced Cr(vi) and sodium pentachlorophenate removal under visible light

Oxygen vacancy induced selective silver deposition on the {001} facets of BiOCl can offer remarkable photocatalytic performance of Ag–BiOCl composites under visible light.