Luyi Zhang

Ecophysiological characteristics and biogas production of cadmium-contaminated crops.

The present study proposes a novel strategy to get a rational production of biogas of the biomass residues from phytoremediation. This study investigates physiological responses, cadmium (Cd) accumulation and biogas production from canola, oat and wheat in pot and batch experiments. The results indicate that (1) aerial biomasses for canola, oat and wheat were enhanced by 5 mg Cd/kg soil by 19.41%, 8.78% and 3.38%, and the upper limit of Cd concentration that canola, oat and wheat can tolerate for aerial biomass production were 50, 10 and 10 mg Cd/kg soil; (2) canola accumulates more Cd than oat and wheat in its aerial parts; (3) cumulative biogas yields were 159.37%, 179.23% and 111.34% of the control when Cd in the shoot were 2.00±0.44, 39.80±1.25 and 6.37±0.15 mg Cd/kg biomass for canola, oat and wheat. Phytoremediation in cooperation with bioenergy production provide new insights for both soil remediation and energy research.

Adsorption of methylene blue from aqueous solutions onto sintering process red mud

Abstract The adsorption behavior of methylene blue (MB) dye from aqueous solutions onto sintering process red mud (SRM) and its hydrochloric acid-activated product (ASRM) was investigated in a batch system. The results showed that equilibrium was reached after a contact time of 60 min for both adsorbents. The optimum pH for MB adsorption was 10.0 for SRM and 9.0 for ASRM. The removal of the dye increased with increasing initial dye concentration and adsorbent amount, whereas it decreased with increasing ionic strength. The effect of temperature on adsorption was also investigated; the adsorption of MB on SRM and ASRM samples was spontaneous and followed an endothermic process, based on the analysis of thermodynamic parameters, including enthalpy (ΔH), entropy (ΔS), and free energy (ΔG) changes. The adsorption of MB followed pseudo-second-order kinetics, with a coefficient of correlation ⩾ 0.9999. The adsorption process was better described by the Langmuir isotherm model than Freundlich model, with a maxim...

Research on anaerobic digestion of corn stover enhanced by dilute acid pretreatment: Mechanism study and potential utilization in practical application

The utilization of lignocelluloses for biogas production is limited for several aspects, and an efficient pre-treatment is essential to increase the enzyme accessibility of cellulose. This research focused on the mechanism of biogas production and biodegradation properties under the treatments with different acid agents, including sulfuric acid (H2SO4), acetic acid (CH3COOH), and phosphoric acid (H3PO4). The H3PO4 pretreated corn stover was then co-digested with cow dung in a pilot test to investigate the performance of acid pretreatment in practice. The results showed that the main compositions of corn stover were cellulose, hemicellulose, and lignin, and their proportions in the corn stovers were increased after the acid pretreatments. This hence increased the final biogas yields (up to 40.75%), methane content, and promoted the biodegradation process. More significantly, the acid pretreatments delayed the appearance of the peak value of the biogas yield for 3 to 8 days depending on the acid concentrations. This study proposed that the dilute weak acid pretreatment, especially H3PO4 pretreatment, efficiently enhanced the biogas production by increasing the degradation of hemicellulose. Further on, the H3PO4 pretreatment also improved the stability of fermentation, which would benefit the biogas generation in practice. This research contributes to a better understanding of the mechanism of acid influence on enhancing the biogas generation and substrate biodegradation, and provides pratically sound guidance for reclamation of lignocellulosic materials.