Preparation and textural characterisation of activated carbon from vine shoots (Vitis vinifera) by H 3 PO 4 —Chemical activation B. Corcho-Corral a , M. Olivares-Marı ´n a , C. Ferna´ndez-Gonza´lez a, * , V. Go´mez-Serrano a , A. Macı ´as-Garcı ´a b a Departamento de Quı ´mica Inorga´nica, Facultad de Ciencias, Universidad de Extremadura, Badajoz, Spain b A ´ rea de Ciencia de Materiales e Ingenierı ´a Metalu´rgica, Escuela de Ingenierı ´as Industriales, Universidad de Extremadura, Avda. de Elvas s/n, 06071 Badajoz, Spain Available online 5 December 2005 Abstract An abundant and low-cost agricultural waste as vine shoots (Vitis vinifera) (VS), which is generated by the annual pruning of vineyards, has been used as raw material in the preparation of powder activated carbon (AC) by the method of chemical activation with phosphoric acid. After size reduction, VS were impregnated for 2 h with 60 wt.% H 3 PO 4 solution at room temperature, 50 and 85 8C. The three impregnated products were carbonised at 400 8C. The product impregnated at 50 8C was heated either first at 150–250 8C and then at 400 8C or simply at 350–550 8C in N 2 atmosphere. The time of isothermal treatment after each dynamic heating was 2 h. The carbons were texturally characterised by gas adsorption (N 2 , 196 8C), mercury porosimetry, and density measurements. FT-IR spectroscopy was also applied. Better developments of surface area and microporosity are obtained when the impregnation of VS with the H 3 PO 4 solution is effected at 50 8C and for the products heated isothermally at 200 and 450 8C. The mesopore volume is also usually higher for the products impregnated and heated at intermediate temperatures. # 2005 Elsevier B.V. All rights reserved. PACS: 61.47.Gt; 68.43.h; 81.05.Rm; 82.45.Jn Keywords: Activated carbon; Vine shoots; Phosphoric acid activation 1. Introduction Activated carbon (AC) is a carbonaceous material which possesses a highly developed porosity and that, as a result, is commonly used in a wide range of applications, concerned principally with the removal of chemical species by adsorption from the liquid or gas phase [1]. The high adsorptive capacities of AC are associated with their internal porosity and related to properties such as surface area, pore volume and pore size distribution. Generally, AC is mainly a microporous solid but, in addition to micropores, it contains meso- and macropores, which are very important pores in facilitating access of the adsorbate molecules to the interior of carbon particles [2]. As is well known, the type of raw material employed and the method of preparation dictate the type of porosity and chemical composition of AC [3,4]. Several coals [5–8], polymers [9,10], and some agricultural by-products and forest wastes [4,11–15] have been used as raw materials to prepare AC. Chemical acti- vation consists of carbonisation in the presence of a dehydrating agent (e.g., ZnCl 2 ,H 3 PO 4 ,H 2 SO 4 ). These chemical agents may promote the formation of cross-links, leading to the formation of a rigid matrix that is further less prone to volatile loss and volume contraction upon heating to high temperatures [16–18]. Vine shoots are a major source of vineyard waste, produced in the annual pruning process. Yearly, between 2 and 4 tonnes of vine shoots are generated in a vineyard [19]. This agricultural by- product poses a problem to farmers who usually burn it in the field. This solution is the fastest one but not the best one, both economically and environmentally. As an alternative, vine shoots can be used as fuel, organic fertiliser, or feed. However, these uses of vine shoots, among others, have drawbacks associated with the low density of the material and transportation cost. In order to diversify the applications of vine shoots to increase the profitability of this agricultural residue and hence its use to the greatest advantage, this work was mainly focussed on the preparation of AC from such a raw material, using www.elsevier.com/locate/apsusc Applied Surface Science 252 (2006) 5961–5966 * Corresponding author. Tel.: +34 924289300x6854; fax: +34 924289395. E-mail address: mcfernan@unex.es (C. Ferna´ndez-Gonza´lez). 0169-4332/$ – see front matter # 2005 Elsevier B.V. All rights reserved. doi:10.1016/j.apsusc.2005.11.007