Removal of Oxytetracycline in Pharmaceutical Effluents by Using Synthetic Adsorbents

Introduction

Antibiotics have saved countless lives since their discovery, large quantities of these drugs are widely administered and used as antimicrobial drugs throughout the world [1]. Antibiotic drugs are predominantly used to treat bacterial diseases in human therapy and as veterinary medicines to prevent diseases in animal husbandry, and function as growth promoters, mainly in livestock [1].

Oxytetracycline (OTC), (a natural metabolic product of a bacterium, Streptomyces Rimosus) [2]. As one kind of typical tetracyclines, possess a wide range of antimicrobial activity against gram-positive and gram-negative bacteria [3]. Tetracyclines is widely used in the clinical treatment and livestock industry, and as growth promoter due to its broad spectrum of activity and low cost [4]. Tetracyclines contribute approximately 50% of total antibiotics production [5]. Due to its wide antibacterial spectrum, Oxytetracycline (OTC) is a common antibiotic used to treat different food-producing animals such as cattle, pigs, sheep and poultry, as well as in dogs and cats and fish. Usually it is administered orally with feed dosage rate of 25–700 mg/kg [6] Oxytetracycline is ionized throughout the pH range, existing in the cationic form below pH 3.3, as a zwitterion between pH 3.3 and 7.7, and an anion above pH 7.7 [7]. Tetracyclines, generally act as bacteriostatic antibiotics, by inhibiting the protein synthesis by reverse binding the 30S ribosomal subunits of susceptible organisms, and preventing access of aminoacyl-tRNA to the acceptor site on the mRNA-ribosome complex. Tetracyclines also are believed to reversibly bind to 50S ribosomes and additionally alter cytoplasmic membrane permeability in susceptible organisms. In high concentrations, tetracyclines can also inhibit protein synthesis by mammalian cells [6]. The widespread production and use of natural tetracyclines in both human and animal medicine in the decades following their discovery led to emergence of resistance mechanisms and decreased effectiveness as front-line antibiotics [8]. OTC affected algae and other bacteria by decreasing their population numbers, while it could cause death to invertebrates and fish [2]. In a natural aquatic system, the available concentration for bioaccumulation depends on how fast the compound is degraded and how much the compound is sorbent in the sediment. Therefore, the bioavailability of OTC for the aquatic organism will vary with the environmental conditions and the consumption behaviors of each aquatic species [2]. The bioaccumulations of OTC in farm animals such as chicken, swine and cow were higher than that found in aquatic species. This is probably because they uptake OTC directly from their feed while aquatic species obtained OTC from their environment [2]. The ingestion of OTC contaminated food could pose a potential risk to human health. Varieties of toxic and irritation effects in humans have been reported ranging from minor effects such as sore throat, nausea and diarrhea to serious illness such as peripheral blood and liver injury [2]. Degradation of OTC is one factor that reduces its concentration in soil, water and sediment, hence decreasing its bioavailability and toxicity to the organism [2]. Several methods reported in the literature for the determination of tetracyclines are expensive, time consuming and are not useful for the routine analysis [3], but adsorption was an old scientific subject and adsorption-based technologies were industrially important that attracted people. As adsorption of tetracyclines, oxytetracycline in the present case, on isolated clays, organic clays, soils, organic matters and marine sediment has been previously investigated [9]. The present work involved a study of the adsorption process of the oxytetracycline (OTC) from aqueous solution by Bentone-34 as adsorbent material. (Bentone 34 is an organic derivative of a special smectite. It is manufactured by chemically modifying naturally occurring clays like bentonite) [10]. Choosing Bentone-34 as adsorbent because of its non-toxicity, adsorption properties and low-cost material. The aim of my study was to develop a simple, accurate, fast, and economical method for removal of OTC in pharma wastewater with minimal materials.

Conclusion

In the present novel study the adsorption of the Oxytetracycline (OTC) from pharma wastewater on bentone-34 clay was investigated. The international council of Harmonization (ICH) guidelines was used for all the analytical validation parameters for this proposed method. For the determination of data analysis Microsoft Excel was used. Beer – Lambert’s law is obeyed in the range 0.214 -1.070 mg/ml. The linear calibration curve was established in the 5 concentration level ranges (0.214-1.070 mg/mL) of OTC. As from the analyzed data the following results for parameters were obtained, as linear regression equation was y =0.1745x+0.0026 with linearity correlation R2 > 0.9984), accuracy (Recovery = 91−98 %), sensitivity (LOD = 42.3 mg/mL; LOQ =48.3 mg/mL), and precision (RSD ≥ 2.0 %) in the respective linear concentration ranges. The method is successfully applied for the removal of OTC as the tested sample improves ICH parameters like accuracy, precision, sensitivity. The results of the present study are indicative of Bentone-34 as a new alternative low-cost adsorbent for removing the oxytetracycline from pharma wastewater.