Use of carbon coated ceramic barriers for adsorptive removal of fluoride and permanent immobilization of the spent adsorbent barriers

Abstract

This work is focused on the coating of carbon particles on a clay based flat ceramic substrate by vacuum driven filtration deposition and its use for the separation of fluoride from contaminated water. A thin and smooth layer of nanoaluminum oxyhydroxide deposited carbon over the porous clay based flat ceramic support was obtained by the simple vacuum suction technique. The coated membrane was able to remove fluoride with good efficiency. Post adsorption barriers containing toxic fluoride ions cannot be simply thrown away but fluoride ions need to be immobilized in it to prevent its leaching from it. Therefore, another important component of the work is the permanent immobilization of fluoride adsorbed membrane (FCM) in cement clinkers by reacting with lime and clay by black meal method of clinker preparation. All the necessary phases like tricalcium silicate (3CaO•SiO 2), dicalcium silicate (2CaO•SiO 2), tricalcium aluminate (3CaO•Al 2 O 3) and tetra calcium aluminoferrite (4CaO•Al 2 O 3 Fe 2 O 3) found in a typical portland cement clinkers are observed in the prepared clinkers and confirmed from X-ray diffractometry. The studies showed that conventional firing temperature of 1450 °C for clinker formation could be lowered to 1350 °C by the addition of fluoride adsorbed ceramic waste due taking advantage of mineralizers such as F − and Al 3+ and the carbonaceous materials which facilitated the firing process. The fluoride leaching studies confirmed the acceptability of the process.

Removal of lead ions (Pb2+) from water and wastewater: a review on the low-cost adsorbents

“…For example, iron oxide nanoparticles were disposed of by immobilizing inside the phosphoric glass matrix (Majumder et al 2019 ). In addition, the adsorbents can be used in the construction industry to form brick (Avinash and Murugesan 2019 ) or as a filler material in the cement industry (Saikia and Goswamee 2019 ).…”