Using alkali metals to control reactivity and porosity during physical activation of demineralised kraft lignin

Demineralised kraft lignin was impregnated with between 6.2% and 50% NaCl or KCl and physically activated in CO2 at 750 C. The results presented show that a considerable reduction in activation time even at a comparatively low activation temperature could be achieved, particularly when using KCl. Considering a fixed level of burn-off, the impregnation did not affect the pore volume and only increased the pore width by about 0.1–0.2 nm, depending on the concentration of NaCl or KCl used. By controlling the conditions it was possible to obtain predominantly ultramicroporous materials with mean pore widths over the range 0.53–0.77 nm. On the other hand, at high levels of burn-off there was evidence for micropore widening into the small mesopore range and also for the formation of a secondary mesopore structure. Under these conditions it was possible to obtain materials with pore volumes as high as 0.82 cm3 g 1

Low-Cost Adsorbents: Growing Approach to Wastewater Treatment—a Review

Industrial, agricultural, and domestic activities of humans have affected the environmental system, resulting in drastic problems such as global warming and the generation of wastewater containing high levels of pollutants. As water of good quality is a precious commodity and available in limited amounts, it has become highly imperative to treat wastewater for removal of pollutants. In addition, the rapid modernization of society has also led to the generation of huge amount of materials of little value that have no fruitful use. Such materials are generally considered as waste, and their disposal is a problem. Also, there are some materials that are available in nature that have little or no use. The utilization of all such materials as low-cost adsorbents for the treatment of wastewater may make them of some value. An effort has been made to give a brief idea of an approach to wastewater treatment, particularly discussing and highlighting in brief the low-cost alternative adsorbents with a view to utilizing these waste/low-cost materials