Hussein Mohd Zobir Bin, Kuang Dzulkefly, Zainal Zulkarnain, Teck Tan Kian
Multifunctional Materials for Industrial Application (MULIA) Research Group, Department of Chemistry, Universiti Putra Malaysia, Serdang, Selangor, 43400UPM, Malaysia
J Colloid Interface Sci. 2001 Mar 1;235(1):93-100. doi: 10.1006/jcis.2000.7175.
Kaolin-carbon adsorbents were prepared with and without sulfuric acid pretreatment followed by activation-carbonization at 500 degrees C. The total surface area of the resulting kaolin-carbon adsorbents was found to be decreased with the increase in kaolin loading. Sulfuric acid pretreatment of the precursor prior to the carbonization-activation processes resulted in the enhancement of total surface area but reduced the micropore surface area of the resulting adsorbents. At the same time, this improved carotene adsorption capacity from red palm oil. However, recovery of carotene from the carotene-adsorbed adsorbent is only improved when the acid pretreatment of the precursor was done at a high loading percentage of activated carbon. Similarly, the peroxide value (PV) increased. A maximum removal of carotene from red palm oil was obtained at 20% kaolin loading for both adsorbents prepared with and without sulfuric acid pretreatment with about 45 and 65% carotene removal, respectively, from a 30-ppm solution. This indicates that pretreatment with sulfuric acid, prior to the activation-carbonization process, increased the carotene uptake by the resulting adsorbent. However, a further increase in the kaolin loading resulted in the decrease of carotene removal. About 3-4% of carotene adsorbed can be recovered from both types of adsorbents under optimum condition, in which the percentage recovered decreased with the increase in kaolin loading. On the other hand, the PV increased with kaolin loading at around 54-64 mEq/kg for both types of adsorbents. It was also found that carotene uptake by the adsorbents is high if the adsorbent contains a high percentage of activated carbon. Similarly, carotene recovery is high and less oxidation can be observed, as indicated by the lower PV value. Copyright 2001 Academic Press.
通过有无硫酸预处理，随后在500摄氏度下进行活化 - 碳化来制备高岭土 - 碳吸附剂。结果发现，随着高岭土负载量的增加，所得高岭土 - 碳吸附剂的总表面积减小。在碳化 - 活化过程之前对前驱体进行硫酸预处理，可提高总表面积，但会降低所得吸附剂的微孔表面积。同时，这提高了从红棕榈油中吸附胡萝卜素的能力。然而，只有当前驱体的酸预处理在高活性炭负载百分比下进行时，从吸附了胡萝卜素的吸附剂中回收胡萝卜素的效果才会得到改善。同样，过氧化值（PV）增加。对于经过硫酸预处理和未经过硫酸预处理制备的两种吸附剂，在高岭土负载量为20%时，从红棕榈油中去除胡萝卜素的效果最佳，从30 ppm的溶液中分别去除约45%和65%的胡萝卜素。这表明在活化 - 碳化过程之前用硫酸预处理可增加所得吸附剂对胡萝卜素的吸收。然而，高岭土负载量的进一步增加会导致胡萝卜素去除率降低。在最佳条件下，两种类型的吸附剂都可回收约3 - 4%吸附的胡萝卜素，其中回收百分比随高岭土负载量的增加而降低。另一方面，两种类型吸附剂的PV值均随高岭土负载量增加，在54 - 64 mEq/kg左右。还发现，如果吸附剂含有高百分比的活性炭，则吸附剂对胡萝卜素的吸收较高。同样，胡萝卜素回收率高，并且如较低的PV值所示，氧化程度较低。版权所有2001年学术出版社。
