Lishan Jia

A novel biomass coated Ag–TiO2 composite as a photoanode for enhanced photocurrent in dye-sensitized solar cells

A novel biomass-coated Ag nanoparticle-modified TiO2 composite was prepared and used as a photoanode in a dye-sensitized solar cell with a high surface area, strong light scattering and efficient electron transport. It was found that syzygium extract has an appreciable effective function as a reducing and stabilizing agent simultaneously. The mean size of the synthesized silver nanoparticles is 4.0 ± 0.7 nm measured on the TEM images. Residual hydroxyl groups of the biomass on the photoanode improve dye absorption and electron injection efficiency. The syzygium-Ag–TiO2 DSSC exhibits the best performance with a short-circuit current of 11.8 mA cm−2 corresponding to a photoelectric conversion efficiency of 5.12%, which is higher than the glucose-Ag–TiO2 and UV-Ag–TiO2 DSSCs, and much higher than the blank DSSC.

Cellulose-derived carbon bearing -Cl and -SO3H groups as a highly selective catalyst for the hydrolysis of cellulose to glucose

A solid acid catalyst (HA–CC–SO3H) was synthesized by the sulfonation of amorphous carbon derived from the carbonization of dilute hydrochloric acid-pretreated microcrystalline cellulose. It was found that Cl− ions are grafted onto the cellulose-derived carbon and affect the composition and structure of the carbon carrier during the carbonization process. The electrons of the aromatic carbons transfer to –Cl and –SO3H groups, which influence their electronic state. In the cellulose hydrolysis process, the active electronic states make the –Cl groups more liable to form hydrogen bonds with cellulose, and the –SO3H groups with stronger acidity easily break the glycosidic bonds of cellulose to produce glucose. The HA–CC–SO3H catalyst exhibits excellent glucose selectivity (95.8%) at a moderate temperature (155 °C) under hydrothermal conditions.

Reversible absorption of SO2 by amino acid aqueous solutions

Six water-soluble amino acids (glycine, l-α-alanine, dl-alanine, β-alanine, proline and arginine) aqueous solutions were applied to remove SO(2) from SO(2)-N(2) system in this report. All the tested amino acids solutions were found to be excellent absorbents for SO(2) removal, and SO(2) saturation uptake of β-alanine solution was the highest under the same experimental conditions. The effects of amino acid concentration, SO(2) concentration, absorption temperature, desorption temperature and initial pH value of the absorbent on the removal of SO(2) were investigated with β-Ala solution. The experimental results showed that SO(2) saturation uptake increased with the increase in β-alanine solution and SO(2) concentration. Room temperature (20-30°C) was found to be optimal for SO(2) absorption. Additionally the SO(2) desorption capacity increased with increasing desorption temperature. The neutral environment pH value of 6.8 was found to be optimal for SO(2) removal. Ten continuous absorption-desorption cycles showed that the absorbent had an excellent regeneration performance. (13)C NMR and ultraviolet analyses offer ample evidence to speculate that the bonding between SO(2) and β-alanine was not covalent but some weak interactive forces, such as dispersion force, induction force, dipole-dipole force and hydrogen bond.

Methanation of carbon dioxide over the LaNiO3 perovskite catalysts activated under the reactant stream

Abstract In this study, LaNiO 3 perovskite catalysts were prepared by citrate method and used for carbon dioxide (CO 2 ) methanation. The catalysts were activated at different temperatures (400–700°C) under the reactant stream. The activation led to the formation of small metallic nickel particles and hexagonal lanthanum oxocarbonate (La 2 O 2 CO 3) . Ni 0 was highly dispersed and enveloped by La 2 O 2 CO 3 , which was responsible for the high catalytic activity and stability of the LaNiO 3 perovskite catalysts even at high temperature (400–500°C). The X-ray diffraction, X-ray photoelectron spectroscopy, transmission electron microscopy, and H 2 -temperature-programmed desorption measurements illustrated that La 2 O 2 CO 3 generated from the activation might play an important role in the methanation of CO 2 .

Utilization of CO2 and biomass char derived from pyrolysis of Dunaliella salina: The effects of steam and catalyst on CO and H2 gas production

Biomass char, by-product of Dunaliella salina pyrolysis at a final pyrolysis temperature of 500°C, was used as feedstock material in this study. The reactions of biomass char with CO(2) were performed in a fixed-bed reactor to evaluate the effect of temperature and steam on the CO(2) conversion, CO yield and gas composition. The CO(2) conversion and CO yield without steam and catalyst reached about 61.84% and 0.99mol/(mol CO(2)) at 800°C, respectively. Steam and high temperature led to high CO(2) conversion. A new approach for improving H(2) was carried out by using biomass char and Au/Al(2)O(3) catalyst, which combined steam gasification of biomass char and water gas shift reaction, and the H(2) concentration was 1.8 times higher than without catalyst. The process not only mitigated CO(2) emission and made use of residual biomass char, but also created renewable source.

Facile sand enhanced electro-flocculation for cost-efficient harvesting of Dunaliella salina

Energy consumption and water resource in the cultivation and harvesting steps still need to be minimized for the popularization of the microalgae-based products. An efficient electro-flocculation method for harvesting Dunaliella Salina integrated with local sand has been successfully applied. Sand was effective for speeding up the processes of flocculation and sedimentation of algal flocs and the electrolytic hydroxides was essential to bridge the sand and small flocs into large dense flocs. The maximal recovery effective improved from 95.13% in 6min to 98.09% in 4.5min and the optimal electrical energy consumption decreased 51.03% compared to conventional electro-flocculation in a laboratory ambient condition. Furthermore, reusing the flocculated medium in cultivation of the D. Salina with nitrogen supplemented performed no worse than using fresh medium. This sand enhanced electro-flocculation (SEF) technology provides a great potential for saving time and energy associated with improving microalgae harvesting.

Optimizing light distribution and controlling biomass concentration by continuously pre-harvesting Spirulina platensis for improving the microalgae production

To improve the microalgae production in batch cultivation, a cultivation mode that continuously pre-harvesting Spirulina platensis from photobioreactor (PBR) with culture medium recycling was proposed. For realizing the continuously pre-harvesting cultivation mode, a Spirulina platensis culture column PBR with overflowing device was designed, which could adjust pre-harvesting rate through the overflowing device. By adjusting the pre-harvesting rate, the biomass concentration could be kept when biomass accumulation and pre-harvesting biomass were equal. Hence, the meridional light attenuation could be reduced by controlling biomass concentration in PBR. The maximum microalgae production were 44.6%, 10.98% higher in total production than that cultivated in batch cultivation without pre-harvesting and periodically pre-harvesting cultivation mode respectively, which was realized in pre-harvesting rate 0.228 mL min-1 and biomass concentration 1.8 g L-1. Besides, a model was built by mass balance and polynomial fitting for evaluating the continuously pre-harvesting cultivation mode.

Energy-producing electro-flocculation for harvest of Dunaliella salina

In this study, an efficient electro-flocculation process for Dunaliella salina with energy production by aluminum-air battery has been successfully applied. The formed aluminum hydroxide hydrates during discharging of battery were positively charged, which have a great potential for microalgae flocculation. The precipitation of aluminum hydroxide hydrates by algae also could improve the performance of aluminum-air battery. The harvesting efficiency could reach 97% in 20mins with energy production of 0.11kWh/kg. This discharging electro-flocculation (DEF) technology provides a new energy producing process to effectively harvest microalgae.