Abstract:
Arsenic (As) is an emerging contaminant on a global scale posing threat to environmental and human health. The
relatively brief history of the applications of biochar and bone char has mapped the endeavors to remove As from
water to a considerable extent. This critical review attempts to provide a comprehensive overview for the first
time on the potential of bio- and bone-char in the immobilization of inorganic As in water. It seeks to offer a
rational assessment of what is existing and what needs to be done in future research as an implication for As
toxicity of human health risks through acute and chronic exposure to As contaminated water. Bio- and bone-char
are recognized as promising alternatives to activated carbon due to their lower production and activation cost.
The surface modification via chemical methods has been adopted to improve the adsorption capacity for anionic
As species. Surface complexation, ion exchange, precipitation and electrostatic interactions are the main mechanisms
involved in the adsorption of As onto the char surface. However, arsenic-bio-bone char interactions
along with their chemical bonding for the removal of As in aqueous solution is still a subject of debate. Hence,
the proposed mechanisms need to be scrutinized further using advanced analytical techniques such as synchrotron-
based X-ray. Moving this technology from laboratory phase to field scale applications is an urgent
necessity in order to establish a sustainable As mitigation in drinking water on a global scale.
