# Biochar as a Multifunctional Component of the Environment--A Review
## 5 Biochar as a Activated Carbons  
In recent years there has been an increase in interest in the use of active coals resulting mainly from their low production cost and favorable physicochemical properties, which include a strongly \begin{table}
\begin{tabular}{c c c c c} \hline \hline \multirow{2}{*}{**Fuel**} & \multirow{2}{*}{**Calorific Value (MJ kg\({}^{-1}\))**} & **Carbon** & **Ash** & **Volatiles** \\ \cline{3-5}  & & & **\%** & \\ \hline \multicolumn{5}{c}{Biomass} \\ \hline Wood & 10.5 & 35.0 & 1.0 & 55.0 \\ Straw & 15.0 & 43.0 & 3.0 & 73.0 \\ Rapeseed & 15.3 & 44.7 & 7.3 & 78.7 \\ Sunflower & 15.7 & 17.2 & 8.3 & 74.5 \\ \hline \multicolumn{5}{c}{Biochar} \\ \hline Biochar from rapeseed & 23.4 & 72.7 & 21.8 & 13.6 \\ Biochar from sunflower & 20.5 & 63.4 & 28.9 & 13.4 \\ Biochar from oil palm (residues) & 17.1 & 53.8 & 3.1 & 81.9 \\ Biochar from cherry wood & 27.7 & 59.5 & 9.1 & 22.2 \\ \hline \hline \end{tabular}
\end{table} 
Table 4: _Cont._ \begin{table}
\begin{tabular}{c c c c} \hline \hline \multirow{2}{*}{**Contamination**} & \multicolumn{2}{c}{**Type of Biochar**} & \multicolumn{2}{c}{**Type of**} \\  & **(Feedstock/Pyrolysis Temperature)** & **Environment** & **References** \\ \hline \multicolumn{4}{c}{_Agricultural chemicals_} \\ \hline Atrazine & Cattle manure (450 \({}^{\circ}\)C) & Soil & [85] \\ Atrazine and simazine & Green waste (450 \({}^{\circ}\)C) & Water & [86] \\ Pentachlorophenol & Bamboo (600 \({}^{\circ}\)C) & Soil & [87] \\ _Antibiotics_ & & & \\ Sulfamethazine & Hardwood (600 \({}^{\circ}\)C) & Water & [88] \\ Sulfamethoxazole & Bamboo (450 and 600 \({}^{\circ}\)C) & Water & [28] \\ Tylosin & Hardwood (850 and 900 \({}^{\circ}\)C) & Water & [89] \\ Tetracycline & Rice husk (450–500 \({}^{\circ}\)C) & Water & [90] \\ _Other hydrocarbons_ & & & \\ Pyrene & & & \\ Trichoroethylene & Peanut shell (300 and 700 \({}^{\circ}\)C) & Water & [93] \\ Naphthalene & Pine needles (100–700 \({}^{\circ}\)C) & Water & [94] \\ _Heavy metals_ & & & \\ Cadmium & _Miscanthus sacchariflorons_ (300–600 \({}^{\circ}\)C) & Water & [95] \\ Aluminum & Rice straw (100–600 \({}^{\circ}\)C) & Water & [29] \\ Lead & Pine wood (300 \({}^{\circ}\)C) & Water & [96] \\ \hline \hline \end{tabular}
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Table 5: Possible biochar applications for immobilizing contaminants in soil and water. developed specific surface, very good ion-exchange properties and high mechanical and chemical durability. In general, any material which contains carbon in its composition in organic compounds may be used to produce active carbons. The raw materials used, activation process, and process parameters determine the physical properties and performance characteristics of the resulting carbon. Modifying these activation properties determines the porosity and pore volume distribution in the carbon. Activated carbon is defined as a carbonaceous material with a large internal surface area and highly developed porous structure resulting from the processing of raw materials under high temperature reactions. It is composed of 87-97% carbon but also contains other elements depending on the processing method used and raw material it is derived from. Activated carbon's porous structure allows it to adsorb materials from the liquid and gas phase. On an industrial scale, the precursors of active carbons include mainly fossil coals, wood, peat, and coconut shells. The literature presents information concerning the production of activated carbons by activating a variety of waste materials such as nut shells, sawdust, straw, fruit stones, straw, sewage sludge and many others [97]. These activities are of justified environmental character as they manage a significant amount of waste and their economic aspect is important as well. The studies carried out so far have highlighted the fact that activated carbons produced from waste materials can show a better sorption capacity than products made from traditional precursors.