Efficacy of Chicken Litter and Wood Biochars and Their Activated Counterparts in Heavy Metal Clean up from Wastewater

Abstract

It is known that properties of activated biochars are tightly associated with those of the original feedstock as well as pyrolysis and activation conditions. This study examined two feedstock types, pine wood shavings and chicken litter, to produce biochars at two different pyrolysis temperatures and subsequently activated by steam, acid or base. In order to measure activation efficiency, all materials were characterized for their properties and ability to remediate two well-known heavy metals of concern: copper and arsenic. Base activated biochars were superior in arsenic adsorption, to acid or steam activated samples, but increase in adsorption was not significant to warrant use. For wood biochars, significant increases of surface functionality as related to oxygen bearing groups and surface charge were observed upon acid activation which led to increased copper ion adsorption. However, oxygen bearing functionalities were not sufficient to explain why chicken litter biochars and steam activated biochars appeared to be significantly superior to wood shavings in positively charged metal ion adsorption. For chicken litter, functionality of respective biochars could be related to phosphate containing groups inherited

Poultry Litter Biochar: An Approach towards Poultry Litter Management – A Review

“…Apparently, poultry litter biochar contain lower carbon content then plant material derived biochars, and this is confirmed by Das et al, (2008) and Isabel M. Lima et al, (2015).…”

“…Isabel M. Lima et al, (2015), studied wood chips biochar and chicken litter biochar for heavy metal adsorption and reported higher ash content in chicken litter (11.6%) and chicken litter derived biochar (13.5 and 40.1%) then wood chips raw (3.08%) and derived biochar (2.6 and 5.6%) at different pyrolysis temperatures (Lima et al, 2015). Higher ash content is particularly useful for low pH soils as a liming agent.…”

“…Isabel M. Lima et al, (2015) used three different activation protocols (acid, base and steam) for pine wood and chicken litter biochars to obtain higher surface area to increase Cu ion adsorption and reported changes in various chemical properties due to biochar activation, which led to significant changes in surface functionality resulting increased copper ion adsorption (Lima et al, 2015).…”

Removing Gaseous NH3 Using Biochar as an Adsorbent

“…This increase in sorption capacity may be attributed to the change in biochar surface charge and decrease in pH resulting from activation. For example, the total surface charge of NA-WS500-AR decreased slightly from 0.37 to 0.00 meq H + /g from steam activation, whereas it increased dramatically to 2.11 meq H + /g from acid activation [19]. The pH of WS500 (VW) increased from 5.3 to 9.6 after steam activation, but decreased to 3.5 after acid activation (Table 4).…”

“…Samples were placed in the retort, heated to 450 °C under breathing air, and activation was done under air for 60 min. More detailed activation procedure can be found elsewhere [19].…”