Pingping Zhang

Electricity generation from macroalgae Enteromorpha prolifera hydrolysates using an alkaline fuel cell

The goal of this work was to develop a method for the direct power generation using macroalgae Enteromorpha prolifera. The process conditions for the saccharification of macroalgae were optimized and a type of alkaline fuel cell contained no precious metal catalysts was developed. Under optimum conditions (170°C and 2% hydrochloric acid for 45min), dilute acid hydrolysis of the homogenized plants yielded 272.25g reducing sugar/kg dry algal biomass. The maximum power density reached 3.81W/m2 under the condition of 3M KOH and 18.15g/L reducing sugar in hydrolysate, higher than any other reported algae-fed fuel cells. This study represents the first report on direct electricity generation from macroalgae using alkaline fuel cells, suggesting that there is great potential for the production of renewable energy using marine biomass.

Electricity generation from banana peels in an alkaline fuel cell with a Cu 2 O-Cu modified activated carbon cathode

Low-cost and highly active catalyst for oxygen reduction reaction is of great importance in the design of alkaline fuel cells. In this work, Cu2O-Cu composite catalyst has been fabricated by a facile laser-irradiation method. The addition of Cu2O-Cu composite in activated carbon air-cathode greatly improves the performance of the cathode. Our results indicate the enhanced performance is likely attributed to the synergistic effect of high conductivity of Cu and the catalytic activity of Cu2O towards the oxygen reduction reaction. Furthermore, an alkaline fuel cell equipped with the composite air-cathode has been built to turn banana peels into electricity. Peak power density of 16.12Wm-2 is obtained under the condition of 3M KOH and 22.04gL-1 reducing sugar, which is higher than other reported low-temperature direct biomass alkaline fuel cells. HPLC results indicate the main oxidation products in the alkaline fuel cell were small organic acids.

Fast photocatalytic degradation of dyes using low-power laser-fabricated Cu2O–Cu nanocomposites

In this study, we report a simple method to controllably synthesize Cu2O–Cu nanocomposites by using a low-power CO2 laser, and application of these nanomaterials for photocatalytic degradation of methylene blue (MB). Our experiments demonstrate that efficient tailoring of the Cu2O–Cu nanocomposites can be realized by accurate control and optimization of the ambient parameters, such as laser energy and NaOH concentration. Compared to hydrothermally fabricated Cu2O–Cu catalysts, the laser-reduced composites exhibit better visible-light photocatalytic activity for MB degradation, which could be attributed to the formation of special catalytically active structures on the nanocomposite surface. Under the conditions of 10 mA laser irradiation and 5 M NaOH addition, the fabricated Cu2O–Cu composites had the highest catalytic activity. The degradation rate of MB is 90.10% after visible-light irradiation for 50 min under the optimum conditions. The as-synthesized Cu2O–Cu composites showed selective dye degradation, and exhibit relatively higher photocatalytic efficiency for positively charged dyes. This work could lead to facile synthesis of high-performance photocatalysts for fast removal of environmentally hazardous dyes from aqueous solution.

Nano Copper Oxide-Modified Carbon Cloth as Cathode for a Two-Chamber Microbial Fuel Cell

In this work, Cu2O nanoparticles were deposited on a carbon cloth cathode using a facile electrochemical method. The morphology of the modified cathode, which was characterized by scanning electron microscopy (SEM) and Brunauer-Emmett-Teller (BET) tests, showed that the porosity and specific surface area of the cathode improved with longer deposition times. X-ray photoelectron spectroscopy (XPS) and cyclic voltammetry (CV) results showed that cupric oxide and cuprous oxide coexisted on the carbon cloth, which improved the electrochemical activity of cathode. The cathode with a deposition time of 100 s showed the best performance, with a power density twice that of bare carbon cloth. Linear sweep voltammetry (LSV) and electrochemical impedance spectroscopy (EIS) results revealed that moderate deposition of nano copper oxide on carbon cloth could dramatically reduce the charge transfer resistance, which contributed to the enhanced electrochemical performance. The mediation mechanism of copper oxide nanocatalyst was illustrated by the fact that the recycled conversion between cupric oxide and cuprous oxide accelerated the electron transfer efficiency on the cathode.

Energy extraction from seaweed under low temperatures by using an alkaline fuel cell

ABSTRACT Marine macroalgae are considered to be one of the most important biomass sources. They can grow rapidly under various conditions, leading to extensive algal blooms. In this work, a reusable solid-acid catalyst, silicotungstic acid, was used to treat the seaweed Enteromorpha prolifera. Under optimum conditions, 237.354 mg/g (23.735%) of total reducing sugar yield was obtained. The hydrolysate was used as the substrate for bioenergy production in an alkaline fuel cell, and the fuel cell achieved the maximum power density of 6.616 W/m2 under the condition of 3 M KOH and 8.572 mg/mL reducing sugar in hydrolysate, which is higher than any other reported algae-fed fuel cells.

A single-chamber microbial fuel cell for rapid determination of biochemical oxygen demand using low-cost activated carbon as cathode catalyst

ABSTRACT The biochemical oxygen demand (BOD) is widely used for the evaluation of water and wastewater quality. However, the conventional method to measure BOD is time-consuming and requires complicated processes. In this study, a Microbial fuel cell (MFC)-based BOD sensor was developed by using low-cost activated carbon as the cathode catalyst. The sensor was calibrated with an aerated nutrient medium containing sodium acetate as the BOD source. When the sensor was operated with an external resistance of 1u2005Ku2005Ω, linear correlation (R2u2009=u20090.9965) was obtained for BOD concentrations ranging from 80 to 1280u2005mg/L in a reaction time of 50u2005h. Besides acetate, glucose/glutamic acid (GGA) and ethanol could also be analyzed by the sensor. In a low concentration range (200u2005mg/L), the relationship between GGA solution concentration and output voltage was in accord with Monod growth kinetics.

Determination of flavonoids and their antioxidant capacities in Chinese Jujube

The objective of this study was to determine flavonoids and their antioxidant capacities in Chinese Jujube. After initial separation by macro-pore resin, extracts of 60% ethanol were further separated by silica gel column and fractionation FJ-1 was obtained. The composition and structure of this fractionation was analyzed by HPLC, IR and HPLC-MS. The ability to eliminate O2• and •OH of this component was analyzed. Content of total flavonoids in Chinese Jujube was 97.98%. FJ-1 was initially determined to be flavonol with molecular weight of 352. When 0.4mg/mL flavonoids was added, 94.6% of •OH and 73.33% of O2• can be eliminated respectively. FJ-1 shows excellent antioxidant capacity and has dose-effect relationship.