Agricultural biomasses as sorbents of some trace metals

The studies of sorption of six metal ions (Cd²⁺, Cu²⁺, Pb²⁺, Zn²⁺, Ni²⁺, Cr³⁺ and Cr(VI)) from by-products of agriculture are taken into account. The Langmuir q_max values obtained with the use of different biomasses are evaluated and, in order to acquire comparable results, the necessity of using molar concentrations is stressed. The main effects of pH on sorption are estimated by considering both the behaviour of metal ions (hydrolysis and hydroxide precipitation) and the effect of pH on coordination, using a simulated example. Some considerations are made on the information that can be obtained using the most common isotherms and on the need to use chemical dimensions rather than weight in order to make comparison among various metal ions (since atomic weight differences deeply alter the significance of parameters in non-chemical units) and to predict the effects of competition between two (or more) of these for the same sorbent sites on the biomass surface.     

Simplified Synthesis of Biomass-Derived Si/C Composites as Stable Anode Materials for Lithium-Ion Batteries

Synthesis of silicon/carbon (Si/C) composites from biomass resources could enable the effective utilization of agricultural products in the battery industry with economical as well as environmental benefits. Herein, a simplified process was developed to synthesize Si/C from biomass, by using a low-cost agricultural byproduct “rice husk (RH)” as a model. This process includes the calcination of RH for SiO₂/C and the reduction of SiO₂/C by Al in molten salts at a moderate temperature. This process does not need the removal of carbon before thermal reduction of SiO₂, which is thought to be necessary to avoid the formation of SiC at elevated temperatures. Thus, carbon derived from biomass can be directly used for Si/C composites for anode materials. The resultant Si/C shows a high reversible capacity of 1309 mAh g⁻¹ and long cycle life (300 cycles). This research advocates a new and simplified strategy for the synthesis of RH-based biomass-derived Si/C, which is beneficial for low-cost, environmentally friendly, and green energy storage applications.     

化学制氢技术研究进展

本文综述了化学制氢技术的新近研究进展.氢能作为一种很有应用前景的载能体,已得到越来越广泛的研究和应用.在化学制氢、电解水制氢、生物制氢这三种制氢模式中,化学制氢仍是近期主要的制氢方式,其中催化重整制氢仍然是大规模制氢的主流.随着燃料电池这一环境友好的发电方式在技术上的不断突破,诸如生物质制氢、金属置换制氢、太阳能制氢、金属氢化物制氢等许多其他的化学制氢技术得到了迅速的发展,并将伴随着燃料电池、氢燃料发动机等技术的发展和应用,一同步入氢能时代.