The Effect of Crosslinker and Pore Generated on Selective Adsorbent (Cu2+) based on Grafting of Acrylic Acid onto Cassava Starch

Abstract

The technology development in many industries nowadays, such as electronic industry produces heavy metal wastes which may pollute our environment. The use of adsorbent as a heavy metal removal from soil and water is one of the efficient process which can be considered to be used. In addition the release of the adsorbate becomes an important way as well because usually those heavy metals still have a high value. The objective of this research is to develop adsorbent based on cassava starch. So, the release process will become easier and will not produce another waste. The adsorbent was produced through the grafting of acrylic acid onto cassava starch by using Fenton initiator. To construct a stable 3-D network, the crosslinker (CL) N,N'-methylenebisacrylamide was added. The variable observed were the amount of CL added (0.5%; 1.5%; 2.5% and 3.5%) and the treatment of generating more pores on starch copolymer. The treatments on starch copolymer observed were single freezing, second freezing, and citric acid modification and carbonization methods. Analysis performed on the adsorbent was % add-on, water absorption and metal adsorption (especially Cu 2+ ion) capacity. The result showed that the used of 2.5% CL produced the highest add-on (47.66 %), the highest water absorption capacity and the highest metal adsorption capacity (0.29g Cu 2+ /g adsorbent) The citric acid modification also produced the highest pores on the adsorbent.

Grafting Starch with Acrylic Acid and Fenton’s Initiator: The Selectivity Challenge

“…Most of the experimental results reported in previous publications [5,8,10], as well as the experimental explorations of several selectivity improvement ideas reported in Section 6, have been obtained from grafting reaction runs in the stainless-steel bench-scale batch reactor depicted in Figure 1. The reactor is fitted with a water jacket connected to a circulating water bath, which has the function of a thermostration system.…”

“…The overhead stirrer with an integrated torque meter allows for the monitoring of viscosity changes throughout the processes. Cassava starch is typically produced in large quantities in tropical areas and has been used in most of these experiments [5,8]. An exploratory study on the influence of reaction variables has been published, with the full details of the experimental system and the reagents [5,8].…”

“…Cassava starch is typically produced in large quantities in tropical areas and has been used in most of these experiments [5,8]. An exploratory study on the influence of reaction variables has been published, with the full details of the experimental system and the reagents [5,8]. From that assessment, a set of typical conditions for a basic ('standard') reaction procedure was chosen.…”

“…Starch grafting has been the subject of research at Groningen University for over two decades now. Results from the first decade were reported in the PhD thesis of Judy Witono [5]. More publications will be cited further on, related to relevant discussion topics.…”

“…Other initiation methods, such as direct starch activation, are discussed in Section 4.1. Cassava starch was used in most experiments and always thermally gelatinized before the start of the grafting reaction [5,8]. Together, these reagents give a homogeneous reaction system that should be relatively easy to scale up.…”