Carbohydrate Polymers 96 (2013) 450–459 Contents lists available at SciVerse ScienceDirect Carbohydrate Polymers jo u r n al homep age: www.elsevier.com/locate/carbpol New calcareous soil–alginate composites for efficient uptake of Fe(III), Mn(II) and As(V) from water Ibrahim M. El-Sherbiny a,b,∗ , Mohammed I. Abdel-Hamid c , Mohamed Rashad d , Abdelnaser S.M. Ali c , Yehia A. Azab c a Zewail University, Zewail City of Science and Technology, 6th October City, 12588 Giza, Egypt b Chemistry Department, Faculty of Science, Mansoura University, ET-35516, Egypt c Botany Department, Faculty of Science, Mansoura University, Mansoura, Egypt d Arid Lands Cultivation and Development Research Institute, Mubarak City for Scientific Research and Technology Applications, New Borg El-Arab, Alexandria, Egypt a r t i c l e i n f o Article history: Received 7 February 2013 Received in revised form 9 April 2013 Accepted 10 April 2013 Available online xxx Keywords: Alginate Brown algae Iron Manganese Arsenic Calcareous soil a b s t r a c t In the present study, various grades of sodium alginates were extracted from different brown macro- algae and their characteristics were investigated using FTIR, UV–vis and EA. The alginates were used in combination with different proportions of calcareous soil to develop new composite microparticles as potential sorbents for efficient uptake of Fe(III), Mn(II) and As(V) from water. Under the investigated conditions (1 g of composite equilibrated in 100 ml of standard metal ion solution), the composites have removed almost 100% of Fe(III) in the concentration range of 0.5–16.0 mg l -1 . Soil, alginate and composites exhibited the highest removal (about 89%) of Mn(II) at 0.5 mg l -1 . Reasonable removal efficiency (50–60%) was recorded at 0.5 mg l -1 of As(V) whereas, increasing the initial As(V) concentration resulted in marked decrease in removal efficiency. The collected equilibrium data were also fitted to both Langmuir and Freundlich isotherms for all the developed composites. © 2013 Elsevier Ltd. All rights reserved. 1. Introduction Heavy metals have a wide range of potential applications in var- ious fields, however many of them are highly toxic even at low concentrations and being non-biodegradable tend to accumulate in living organisms and cause different diseases and health dis- orders (Reddy, Seshaiah, Reddy, Rao, & Wang, 2010). Hence, such heavy metals must be removed from the polluted water streams in response to environmental legislation and enforcement. Besides, polluted water streams and groundwater often contains some heavy metals such as iron and manganese, which can not only affect the color and flavor of water but also accumulate to cause hin- drance in the water equipment and pipelines (Gotoh, Matsushima, & Kikuchi, 2004). Iron, manganese and arsenic are three of the major toxic metal ions that are hazardous to life. Iron levels below 0.3 mg l -1 were characterized as unnoticeable, whereas iron concentrations in the range of 0.3–3 mg l -1 were considered acceptable (WHO, 1996). ∗ Corresponding author at: Chemistry Department, Faculty of Science, Mansoura University, ET-35516, Egypt. Tel.: +20 106 333 0913. E-mail address: imelsherbiny@gmail.com (I.M. El-Sherbiny). Manganese is naturally occurring in various groundwaters and surface water sources and also in soils that may erode into these waters. On the other hand, human activities are also responsible for a significant part of the manganese contamination in water in some regions. In higher concentrations, iron and manganese were also found to cause various problems such as staining laundry and water use fixtures, developing a metallic or vinyl type taste in the water, often appearing as a crusty sheen on the water’s surface and suppor- ting the growth of iron and manganese bacteria, which can clog strainers, valves and pumps. Arsenic, a toxic trace element, occurs in both natural and industrial waters. Recently, arsenic contamination of surface and groundwater at toxic levels has become a growing concern on a global perspective. Besides, there have been several reports of arsenic poisoning in various countries such as India (Das et al., 1996), Bangladesh (Hoque et al., 2000), Vietnam (Berg et al., 2001) China, and Taiwan (Tseng et al., 1968). It has been found that long-term drinking of water contaminated with arsenic can cause kidney, bladder, lung, liver, skin, and nerve tissues injuries (Roberts et al., 2004; Thirunavukkarasu, Viraraghavan, & Subramanian, 2003). Over the last few decades, a significant body of research has focused mainly on developing more effective approaches for 0144-8617/$ – see front matter © 2013 Elsevier Ltd. All rights reserved. http://dx.doi.org/10.1016/j.carbpol.2013.04.021