Title: Recycling of defatted Carica papaya seeds biosorbent (DPS) waste containing Pb and Cd in clay bricks: laboratory scale experiment

Authors: Gilbert Umaye Adie; Juergen G. Heinrich; Oladele Osibanjo

Addresses: Chemical Sciences Department, College of Natural Sciences, Redeemer's University, km 46/48 Redemption City, Mowe, Ogun State, P.O. Box 7914, Ikeja, Lagos, P.M.B.2011, Sagamu, Abeokuta, Nigeria; Chemistry Department, Faculty of Science, University of Ibadan, Ibadan, Nigeria ' Ceramic Engineering Department, Institute of Non-metallic Materials, Technical University of Clausthal, Zehntnerstraße 2a.38678, Clausthal-Zellerfeld, Germany ' Chemistry Department, Faculty of Science, University of Ibadan, Ibadan, Nigeria

Abstract: This study investigated the potential of recycling defatted Carica papaya seeds biosorbent (DPS) waste with adsorbed Pb and Cd in clay bricks. Physico-chemical, microscopic and technological properties were performed on raw materials and fired probes incorporated with 0 wt.% to 15 wt.% DPS made by dry compression technique, dried and fired at 700°C, 800°C and 900°C. Leaching tests were conducted on fired probes to ascertain their environmental safety. Incorporation of DPS had remarkable influence on properties of fired materials. Water absorption and total linear shrinkage increased with increase in DPS content while compressive strength decreased. The properties of fired probes with ≤ 6 wt.% DPS achieved ASTM minimum requirement for Class 1 building bricks. Leaching tests on 6 wt.% DPS complied with EPA limits for Pb.

Keywords: recycling; Carica papaya seeds; biosorbents; clay bricks; heavy metals; waste management; lead; cadmium; leaching tests; environmental safety; water absorption; total linear shrinkage; compressive strength.

DOI: 10.1504/IJEP.2013.053184

International Journal of Environment and Pollution, 2013 Vol.51 No.1/2, pp.106 - 120

Received: 24 Dec 2011
Accepted: 17 Jun 2012
Published online: 28 Feb 2014 *

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