Correction to: Emerging technologies for the pretreatment of lignocellulosic materials for bio-based products.

This corrects the article "Emerging technologies for the pretreatment of lignocellulosic materials for bio-based products" in volume 104, with page no 455-473, (https://doi.org/10.1007/s00253-019-10158-w).

Emerging technologies for the pretreatment of lignocellulosic materials for bio-based products.

Exploring a cheap and clean renewable energy has become a common destination round the world with the depletion of oil resources and the concerns of increasing energy demands. Lignocellulosic biomass is the most abundant renewable resource in the biosphere, and the total biomass formed by plant photosynthesis reached more than 200 billion tons every year. Cellulase and hemicellulose and lignin degradation enzymes, the efficient biocatalyst, could efficiently convert the lignocellulosic biomass into sugars that could be further processed into biofuels, biochemical, and biomaterial for human requirement. The utilization and conversion of cellulosic biomass has great significance to solve the problems such as environmental pollution and energy crisis. Lignocellulosic materials are widely considered as important sources to produce sugar streams that can be fermented into ethanol and other organic chemicals. Pretreatment is a necessary step to overcome its intrinsic recalcitrant nature prior to the production of important biomaterial that has been investigated for nearly 200 years. Emerging research has focused in order of economical, eco-friendly, and time-effective solutions, for large-scale operational approach. These new mentioned technologies are promising for lignocellulosic biomass degradation in a huge scale biorefinery. This review article has briefly explained the emerging technologies especially the consolidated bioprocessing, chemistry, and physical base pretreatment and their importance in the valorization of lignocellulosic biomass conversion.

Electron transferring with oxygen defects on Ni-promoted Pd/Al2O3 catalysts for low-temperature lean methane combustion.

Methane (CH4) is the second most consequential greenhouse gas after CO2, with a substantial global warming potential. The CH4 catalytic combustion offers an efficient method for the elimination of CH4. However, improving the catalytic performance of Pd-based materials for low-temperature CH4 combustion remains a big challenge. In this study, we synthesized an enhanced Pd/5NiAlOx catalyst that demonstrated superior catalytic activity and improved water resistance compared to the Pd/Al2O3 catalyst. Specifically, the T90 was decreased by over 100 °C under both dry and wet conditions. Introducing Ni resulted in an enormously enhanced number of oxygen defects on the obtained 5NiAlOx support. This defect-rich support facilitates the anchoring of PdO through increased electron transfer, thereby inhibiting the production of high-valence Pd(2+δ)+ and stimulating the generation of unsaturated Pd sites. Pd0 can effectively activate surface oxygen and PdO plays a significant role in activating CH4, resulting in high activity for Pd/5NiAlOx. On the other hand, the increased water resistance of Pd/5NiAlOx was mainly due to the generation of *OOH species and the lower accumulation of surface -OH species during the reaction process.

Adsorption of cerium (III) by HKUST-1 metal-organic framework from aqueous solution.

Cerium is an important rare earth element (REE), which can be used for many high-tech applications. From the industrial and environmental viewpoints, it is imperative to recover Ce3+ ions from aqueous solution. Herein, HKUST-1 metal-organic framework (MOF) was applied for adsorption and recovery of Ce3+ from aqueous solution. HKUST-1 showed a high adsorption efficiency and remarkable capacity of 353 mg/g at pH = 6. The isotherm, kinetics, effect of pH value and adsorption mechanism of the Ce3+ adsorption process were also studied. The results showed that the adsorption process fitted the Langmuir adsorption model, and the pseudo-second-order model described the kinetics well. The mechanism and reusability in Ce3+ adsorption were systematically investigated by various characterization techniques, suggesting the possible ion exchange between Ce3+ and Cu2+ and the formation of CeO covalent bonding. This work opens up a new way for Ce3+ recovery from water.

Ultrafast and Stable CO2 Capture Using Alkali Metal Salt-Promoted MgO-CaCO3 Sorbents.

As a potential candidate for precombustion CO2 capture at intermediate temperatures (200-400 °C), MgO-based sorbents usually suffer from low kinetics and poor cyclic stability. Herein, a general and facile approach is proposed for the fabrication of high-performance MgO-based sorbents via incorporation of CaCO3 into MgO followed by deposition of a mixed alkali metal salt (AMS). The AMS-promoted MgO-CaCO3 sorbents are capable of adsorbing CO2 at an ultrafast rate, high capacity, and good stability. The CO2 uptake of sorbent can reach as high as above 0.5 gCO2 gsorbent-1 after only 5 min of sorption at 350 °C, accounting for vast majority of the total uptake. In addition, the sorbents are very stable even under severe but more realistic conditions (desorption in CO2 at 500 °C), where the CO2 uptake of the best sorbent is stabilized at 0.58 gCO2 gsorbent-1 in 20 consecutive cycles. The excellent CO2 capture performance of the sorbent is mainly due to the promoting effect of molten AMS, the rapid formation of CaMg(CO3)2, and the plate-like structure of sorbent. The exceptional ultrafast rate and the good stability of the AMS-promoted MgO-CaCO3 sorbents promise high potential for practical applications, such as precombustion CO2 capture from integrated gasification combined cycle plants and sorption-enhanced water gas shift process.

Carboxylation of terminal alkynes with CO2 using novel silver N-heterocyclic carbene complexes.

Four novel N-heterocyclic carbene (NHC) silver complexes, , have been synthesized and characterized. The single X-ray crystal diffraction data indicate a dinuclear solid-state structure for and and a mononuclear structure for and . These complexes have been successfully used as efficient catalysts for the C-H activating carboxylation of terminal alkynes with CO2. A wide range of substrates with various functional groups afforded the corresponding aryl or alkyl substituted propiolic acids in good yields under mild conditions. Moreover, the role of bases and the reaction mechanism is thoroughly discussed.

Hydrolysis of cellulose catalyzed by quaternary ammonium perrhenates in 1-allyl-3-methylimidazolium chloride.

Quaternary ammonium perrhenates were applied as catalyst to promote the hydrolysis of cellulose in 1-allyl-3-methylimidazolium chloride ([Amim]Cl). The quaternary ammonium perrhenates displayed good catalytic performance for cellulose hydrolysis. Water was also proven to be effective to promote cellulose hydrolysis. Accordingly, 97% of total reduced sugar (TRS) and 42% of glucose yields could be obtained under the condition of using 5mol% of tetramethyl ammonium perrhenate as catalyst, 70µL of water, ca. 0.6mmol of microcrystalline cellulose (MCC) and 2.0g of [Amim]Cl as solvent under microwave irradiation for 30min at 150°C (optimal conditions). The influence of quaternary ammonium cation on the efficiency of cellulose hydrolysis was examined based on different cation structures of perrhenates. The mechanism on perrhenate catalyzed cellulose hydrolysis is also discussed, whereas hydrogen bonding between ReO4 anion and hydroxyl groups of cellulose is assumed to be the key step for depolymerization of cellulose.

[Study on fermentation of n-paraffin for producing mixed dicarboxylic acids].

A mutant of Candida tropicalis FYD-2 was obtained from its parental strain SFP-1186 by ultraviolet treatments. On shaking flask, the yield of mixed dicarboxylic acid(DCA) by the mutant was 21.4% higher than that by its ancestor. The amount of mixed DCA reached 156 g/L for 120 h incubation in a 10 L autoconrolled fermentor where the culture medium contained 25% n-paraffin. The process of induced and screening mutant was introduced and the time course of fermentation in 10 L fermentor was discussed.

Fabrication of hollow spheres by dry-gel conversion and its application in the selective hydrodesulfurization of FCC gasoline.

Hollow spheres were synthesized from MCM-41 solid spheres by dry-gel conversion. It was found that water amount has a major impact on the formation of hollow spheres. Transmission electron microscopy (TEM) images revealed that the hollow spheres are between 500 and 600 nm in size with a dense shell of ca. 100 nm. The synthesized hollow sphere sample was examined as a support for hydrodesulfurization catalyst. The sulfur removal was enhanced while olefin hydrogenation of FCC gasoline was suppressed, and thus, the octane value was preserved when the hollow spheres (Na type) were loaded with Ni and Mo oxides as catalyst.