Copper-Catalyzed Aerobic Cross-Dehydrogenation Coupling of Indoles for Synthesis of 2,3'-Bisindoles.

2,3'-Bisindoles with C-C linkages have attracted interest in medicinal chemistry, yet their synthesis is intricate with many steps. Notably, direct C-H/C-H cross-coupling of non-directed heteroaromatics remains challenging, often requiring precious metals and oxidants to enhance coupling efficiency. Herein, we present a copper-catalyzed C-H/C-H cross-coupling method for N-substituted indoles without directing groups, facilitated by molecular oxygen under gentle conditions.

Characterizing hazardous substances of shale gas wastewater from the upper Yangtze River: A focus on heavy metals and organic compounds.

In the last decade, rapid shale gas exploration in upper Yangtze River ecological zone in China has led to increasing concerns about the environmental impact of shale gas wastewater (SGW). However, our understanding of the types of potential hazardous substances of SGW remains limited. In this study, eight SGW samples from three shale gas regions in upper Yangtze River: the Sichuan Basin, the Guizhou Plateau, and the Three Gorges Area were collected, and their general water quality, trace metals, and organic compounds were comprehensively analyzed.

Efficient removal of organic compounds from shale gas wastewater by coupled ozonation and moving-bed-biofilm submerged membrane bioreactor.

Shale gas wastewater (SGW) with complex composition and high salinity needs an economical and efficient method of treatment with the main goal to remove organics. In this study, a coupled system consisting of ozonation and moving-bed-biofilm submerged membrane bioreactor (MBBF-SMBR) was comprehensively evaluated for SGW treatment and compared with a similar train comprising ozonation and submerged membrane bioreactor (SMBR) without addition of carriers attaching biofilm. The average removal rates of MBBF-SMBR were 77.

Efficient integrated module of gravity driven membrane filtration, solar aeration and GAC adsorption for pretreatment of shale gas wastewater.

Low-cost and efficient treatment processes are urgently needed to manage highly decentralized shale gas wastewater, which seriously threatens the environment if not properly treated. We propose a simple integrated pretreatment process for on-site treatment, whereby gravity driven membrane filtration is combined with granular activated carbon (GAC) adsorption and solar aeration. The rationale of exploitment of sustainable solar energy is that most shale gas production areas are decentralized and located in desert/rural areas characterized by relatively scarce transportation and power facilities but also by abundant sunshine.

On-Site Treatment of Shale Gas Flowback and Produced Water in Sichuan Basin by Fertilizer Drawn Forward Osmosis for Irrigation.

Fertilizer drawn forward osmosis (FDFO) was proposed to extract fresh water from flowback and produced water (FPW) from shale gas extraction for irrigation, with fertilizer types and membrane orientations assessed. The draw solution (DS) with NHHPO displayed the best performance, while the DS with (NH)HPO resulted in the most severe membrane fouling. The DS with KCl and KNO led to substantial reverse solute fluxes.

Reuse of shale gas flowback and produced water: Effects of coagulation and adsorption on ultrafiltration, reverse osmosis combined process.

The shale gas flowback and produced water (FPW) from hydraulic fracturing in the Sichuan province of China has relatively low to moderate levels of total dissolved solids (<20 g/L) and organics (<50 mg/L of dissolved organic carbon). As such, a combined ultrafiltration (UF), reverse osmosis (RO) system can be successfully applied to desalinate this feed water with the goal of reuse. However, the concentration of influent organic matter and particulates in the UF and RO stage is high, and the overall ionic and organics composition is highly complex, so that the membrane processes do not perform well, also due to fouling.

Smart ultrafiltration membrane fouling control as desalination pretreatment of shale gas fracturing wastewater: The effects of backwash water.

Background: Increasing attention is being paid to the treatment of shale gas fracturing wastewater, including flowback and produced water (FPW). Energy-efficient pretreatment technologies suitable for desalinating and reusing FPW are of paramount importance.

Objectives: This work focused on enhanced fouling alleviation of ultrafiltration (UF) as a pretreatment for desalinating shale gas FPW in Sichuan Basin, China.

Removal of calcium and magnesium ions from shale gas flowback water by chemically activated zeolite.

Shale gas has become a new sweet spot of global oil and gas exploration, and the large amount of flowback water produced during shale gas extraction is attracting increased attention. Internal recycling of flowback water for future hydraulic fracturing is currently the most effective, and it is necessary to decrease the content of divalent cations for eliminating scaling and maintaining effectiveness of friction reducer. Zeolite has been widely used as a sorbent to remove cations from wastewater.