Elsevier

Bioresource Technology

Volume 146, October 2013, Pages 519-524
Bioresource Technology

Removal of Ni (II) ions from aqueous solutions using modified rice straw in a fixed bed column

https://doi.org/10.1016/j.biortech.2013.07.146Get rights and content

Highlights

  • Removal of Ni (II) ions using modified rice straw in a packed column is proposed.

  • Experiment relies on different bed height and influent Ni (II) concentration.

  • The Adams–Bohart, Thomas and Yoon–Nelson models used to predict model parameters.

Abstract

This paper investigates the ability of modified rice straw, an agricultural biomaterial, to remove Ni (II) ions from aqueous solution in a fixed-bed column. The experiments were performed with different bed heights (1.5 and 2.0 cm), influent Ni (II) concentrations (50, 75 and 100 mg/L) using flow rates (500 μl/min) in order to obtain experimental breakthrough curves. The maximum adsorption capacity of rice straw powder (RSP) was 43 mg/L at 75 mg/L influent concentration of divalent Ni (II) ions at 2 cm bed depth. Adams–Bohart model, Thomas model and Yoon and Nelson kinetic models were used to analyze the column performance. The value of rate constant for Adams–Bohart and Yoon and Nelson model decreased with increase of influent concentration, but increased with increasing bed depth. The rate constant for Thomas model increased with initial influent Ni (II) ions concentration, decreased with increase in bed depth.

Introduction

Pollution by heavy metal ions is one of the major environmental problems. This is due to rapid industrialization, which has created a major global concern. Aqueous effluents emanating from many industries contain dissolved heavy metals (Keng et al., 2013, Yadav et al., 2013). If these discharges are emitted without treatment, they may have an adverse impact on the environment. Ni (II) ions are used in large amounts in leather tanning, electroplating, cement, photography and in dye industries (Adedirin et al., 2011, Kadirvelu et al., 2001a). Ni (II) ions can exist as Ni0 or Ni2+ These are carcinogenic in animals (Sekhon and Gill, 2013) and most frequently encountered in waste water effluent released from industries, such as non-ferrous metal, mineral processing, electroplating, copper sulfate manufacturing, and battery and accumulator manufacturing. Permissible limits for Ni (II) ions in drinking water given by World Health Organization (WHO) are 0.01 mg/L. Higher concentration can cause lung cancer, nose and bone related diseases.

Acute poisoning of Ni (II) ions leads to severe headache, dry cough, shortness of breath, rapid respiration, cyanosis, extreme weakness dizziness, vomiting, chest pain and sickness (Malkoc, 2011). The increased awareness of the toxicity of heavy metals has led to a dramatic increase in research on various strategies that may be employed to clean up the environment. The methods currently used for removal of heavy metals includes solvent extraction, ion-exchange, electroflotation, membrane separation, reverse osmosis, chemical precipitation, and electro dialysis (Yadav et al., 2013) which are expensive and can result in the generation of toxic sludge that is another serious problem (Pahlavanzadeha et al., 2010). The limitation faced by physical and chemical treatment technologies could be overcome with the help of agriculture wastes (Lehmann et al., 1999).

The ability of some agricultural wastes to adsorb heavy metals from aqueous effluents has been reported in literature (Shukla et al., 2002, Kadirvelu et al., 2001b, Yu et al., 2001). Rice (Oryza sativa L.) is the world’s second largest cereal crop after wheat and more than 50% of the world’s population used it as staple food. At least 114 countries in the world grow rice and it produces large amounts of crop residues. Only about 20% of rice straw is used for purposes such as ethanol, paper, fertilizers and fodders. Rice straw burning is a common post-harvest practice and cause’s air pollution called the “Black Cloud” (Kögel-Knabner et al., 2010).

Rice straw is one of the most abundant lignocellulosic waste materials overall the world. Rice straw has many characteristics which make it a potential adsorbent with binding sites that are capable to remove metals from aqueous solutions. Chemical composition of rice straw is predominantly contains cellulose (32–47%), hemicellulose (19–27%) and lignin (5–24%) (Tarley et al., 2004).

The objective of the present study is to evaluate the efficiency of rice straw bed column for removing and recovering heavy metals from contaminated industrial effluent through continuous system. The effects of different parameters, such as column bed depth and influent Ni (II) ions concentration were investigated using a laboratory scale fixed-bed column. The % removal efficiency curves for the adsorption of Ni (II) were analyzed and Adams–Bohart, Thomas and Yoon–Nelson models were also analyzed to study the dynamic behavior of the column.

Section snippets

Preparation of rice straw powder

Rice straw was collected from a cultivated area near Patiala, in Punjab, India. It was washed with de-ionized water several times and was heated in an oven at 60 °C for 72 h to remove all the moisture present in the material. Oven-dried straw crushed, grounded and then sieved to desired mesh size (300–500 μm) for use. This powder was stored in glass bottle prior to use.

Modification of the rice straw powder

Rice straw was treated with sodium hydroxide (0.1 M) solution to increase the adsorption property of the adsorbent (Tarley et al.,

Effect of influent concentration on % removal efficiency

The sorption column data were evaluated and presented in Electronic Supplementary Tables 1 and 2. Parameters in fixed-bed column for adsorption of Ni (II) ion presented in Electronic Supplementary Tables 1 and 2 for bed depth of 2 and 1.5 cm respectively. It was detected from the Electronic Supplementary Figs. 1 and 2 that the% adsorption decreased with increase in initial concentration of the metal. But the uptake capacity increased with increase in initial concentration, which may be due to

Conclusion

Ni (II) ions biosorption by modified RSP was studied, using a fixed bed column. The modified RSP efficiently removed Ni (II) ions in fixed bed column. Uptake of Ni (II) ions through a fixed-bed column was dependent on the bed depth, influent concentration. The maximum adsorption capacity was at 75 mg/L influent concentration and 2 cm bed depth. The Thomas, Adam–Bohart and Yoon–Nelson models were successfully used to predict the breakthrough curves, indicating that they were very suitable for

Acknowledgements

The authors thank the Chairperson, Department of Biotechnology, and Dr. Kashmir Singh in Biotechnology, Panjab University, for providing necessary facilities.

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