Vol.:(0123456789) 1 3 Model. Earth Syst. Environ. DOI 10.1007/s40808-017-0358-0 ORIGINAL ARTICLE Statistical methodology for biosorption of nitrate (NO 3 − ) ions from aqueous solution by Pleurotus eryngii fungal biomass Farah Amin 1  · Farah Naz Talpur 1  · Aamna Balouch 1  · Hassan Imran Afridi 1  · Muhammad Ali Surhio 1   Received: 30 June 2017 / Accepted: 3 August 2017 © Springer International Publishing AG 2017 Introduction Contamination of water resources by excessive presence (high concentrations) of nitrogen compounds such as NO 3 − has become a serious concern worldwide over the past few decades (Nasreen and Rafque 2012). The profound exploitation of nitrogen based fertiliz- ers and the uncontrolled discharges of raw from indus- trial processes have been known to cause the difusion of large NO 3 − quantities into the ground and surface waters (Rezaee Godini et al. 2008). Further important sources of NO 3 − in water system are; degradation of nitrogen contain- ing compounds from natural sources as soil, bedrock and organic materials, agricultural and urban runof, disposal of untreated sanitary and industrial wastes in unsafe manner, leakage in septic systems, landfll leachate, animal manure, NO x air stripping waste from air pollution control devices, the wastes of the production of explosives, decomposition of decaying organic matters buried in the ground and the plan- tation of leguminosae crops which fx atmospheric nitrogen in the form of NO 3 − (Batheja et al. 2009; Afkhami 2003; Okafor and Ogbonna 2003; Mishra and Patel 2009a, b). Owing to its high water solubility, NO 3 − becomes the most widespread groundwater contaminant in the world, imposing a serious threat to drinking water supplies and causing ecological disturbances. Increasing NO 3 − concen- trations in drinking water causes two adverse health efects: induction of blue-baby syndrome (methemoglobinemia) in infants, and the potential formation of carcinogenic nitrosa- mines in adults. Moreover, high amounts of NO 3 − in adults also cause abdominal pain, blood in stool and urine, weak- ness, mental depression, dyspepsia, headache, diarrhea, vomiting, diabetes, hypertension, respiratory tract infections and changes in the immune system (Batheja et al. 2009; Afkhami 2003; Lohumi et al. 2004; WHO 1985; Wright Abstract In the present study, Central Composite Design (CCD) of Response Surface Methodology was employed to investigate the efects of diferent operating conditions on the removal of nitrate (NO 3 − ) ions from aqueous solu- tion onto Pleurotus eryngii dried fungal biosorbent. A three level, three factors CCD was used to evaluate the efects and interactions of the process variables, i.e., solution pH, biosorbent dose and initial NO 3 − concentration. The sec- ond order mathematical model was developed by regression analysis of the experimental data of 17 batch runs. Analy- sis of Variance, F test, Student’s t test and lack of ft test showed that NO 3 − ions biosorption were slightly concen- tration dependent, but markedly increases with solution pH and biosorbent dose. The optimum pH (7.47), biosorbent dose (0.29 g) and initial concentration (772.02 mg L −1 ) were found by desirability function. Under these optimum combi- nations of process parameter conditions, maximum removal of 88.38% was obtained that assisting its use in larger scale. P. eryngii has been characterized by using diferent physico- chemical methods. The characterization suggested a possible contribution of carboxyl and hydroxyl groups in the process of biosorption. Hence, it is suggested that P. eryngii has potential for biosorption as a low-cost and efective sorbent for NO 3 − removal from aqueous solution. Keywords Pleurotus eryngii · Nitrate · Biosorption · Response surface methodology · Characterization * Farah Naz Talpur farahtalpur@hotmail.com http://www.ceacsu.edu.pk 1 National Centre of Excellence in Analytical Chemistry, University of Sindh, Jamshoro 76080, Pakistan