TY  - JOUR
A1  - Unuabonah, Emmanuel I.
A1  - Günter, Christina
A1  - Weber, Jens
A1  - Lubahn, Susanne
A1  - Taubert, Andreas
T1  - Hybrid Clay - a new highly efficient adsorbent for water treatment
JF  - ACS sustainable chemistry & engineering
N2  - New hybrid clay adsorbent based on kaolinite clay and Carica papaya seeds with improved cation exchange capacity (CEC), rate of heavy metal ion uptake, and adsorption capacity for heavy metal ions were prepared. The CEC of the new material is ca. 75 meq/100 g in spite of the unexpectedly low surface area (approximate to 19 m(2)/g). Accordingly, the average particle size of the hybrid clay adsorbent decreased from over 200 to 100 pm. The hybrid clay adsorbent is a highly efficient adsorbent for heavy metals. With an initial metal concentration of 1 mg/L, the hybrid clay adsorbent reduces the Cd2+, Ni2+, and Pb2+ concentration in aqueous solution to <= 4, <= 7 and <= 20 mu g/L, respectively, from the first minute to over 300 min using a fixed bed containing 2 g of adsorbent and a flow rate of approximate to 7 mL/min. These values are (with the exception of Pb2+) in line with the WHO permissible limits for heavy metal ions. In a cocktail solution of Cd2+, and Ni2+, the hybrid clay shows a reduced rate of uptake but an increased adsorption capacity. The CEC data suggest that the adsorption of Pb2+, Cd2+, and Ni2+ on the hybrid clay adsorbent is essentially due to ion exchange. This hybrid clay adsorbent is prepared from materials that are abundant and by a simple means that is sustainable, easily recovered from aqueous solution, nonbiodegradable (unlike numerous biosorbent), and easily regenerated and is a highly efficient alternative to activated carbon for water treatment.
KW  - Kaolinite
KW  - Hybrid clay
KW  - Water treatment
KW  - Cation exchange Capacity
KW  - Adsorbent
KW  - Kinetics
Y1  - 2013
U6  - https://doi.org/10.1021/sc400051y
SN  - 2168-0485
VL  - 1
IS  - 8
SP  - 966
EP  - 973
PB  - American Chemical Society
CY  - Washington
ER  - 
TY  - JOUR
A1  - Unuabonah, Emmanuel I.
A1  - Kolawole, Matthew O.
A1  - Agunbiade, Foluso O.
A1  - Omorogie, Martins O.
A1  - Koko, Daniel T.
A1  - Ugwuja, Chidinma G.
A1  - Ugege, Leonard E.
A1  - Oyejide, Nicholas E.
A1  - Günter, Christina
A1  - Taubert, Andreas
T1  - Novel metal-doped bacteriostatic hybrid clay composites for point-of-use disinfection of water
JF  - Journal of Environmental Chemical Engineering
N2  - This study reports the facile microwave-assisted thermal preparation of novel metal-doped hybrid clay composite adsorbents consisting of Kaolinite clay, Carica papaya seeds and/or plantain peels (Musa paradisiaca) and ZnCl2. Fourier Transformed IR spectroscopy, X-ray diffraction, Scanning Electron Microscopy and Brunauer-Emmett-Teller (BET) analysis are employed to characterize these composite adsorbents. The physicochemical analysis of these composites suggests that they act as bacteriostatic rather than bacteriacidal agents. This bacterostactic action is induced by the ZnO phase in the composites whose amount correlates with the efficacy of the composite. The composite prepared with papaya seeds (PS-HYCA) provides the best disinfection efficacy (when compared with composite prepared with Musa paradisiaca peels-PP-HYCA) against gram-negative enteric bacteria with a breakthrough time of 400 and 700 min for the removal of 1.5 x10(6) cfu/mL S. typhi and V. cholerae from water respectively. At 10(3) cfu/mL of each bacterium in solution, 2 g of both composite adsorbents kept the levels the bacteria in effluent solutions at zero for up to 24 h. Steam regeneration of 2 g of bacteria-loaded Carica papaya prepared composite adsorbent shows a loss of ca. 31% of its capacity even after the 3rd regeneration cycle of 25 h of service time. The composite adsorbent prepared with Carica papaya seeds will be useful for developing simple point-of-use water treatment systems for water disinfection application. This composite adsorbent is comparatively of good performance and shows relatively long hydraulic contact times and is expected to minimize energy intensive traditional treatment processes.
KW  - Kaolinite
KW  - Composites
KW  - Bacteria
KW  - Breakthrough time
KW  - Regeneration
Y1  - 2017
U6  - https://doi.org/10.1016/j.jece.2017.04.017
SN  - 2213-3437
VL  - 5
SP  - 2128
EP  - 2141
PB  - Elsevier
CY  - Oxford
ER  -