References
  -  Y. Guo, P.S. Qi, Y.Z. Liu, A review on advanced treatment of
    pharmaceutical wastewater, IOP Conf. Ser. Earth Environ. Sci.,
    63 (2017) 012025. 
-  R. Baskaran, S.R. Selvi, Desalination of well water solar power
    membrane distillation and reverse osmosis and its effective
    analysis, Int. J. Chemtech. Res., 6 (2014) 2628–2636. 
-  R. Baskaran, S.R. Selvi, Solar photo voltaic powered membrane
    distillation as sustainable clean energy technology in
    desalination, Curr. Sci. India, 109 (2015) 1247–1254. 
-  R. Baskaran, S.R. Selvi, Application of regression modelling
    techniques in desalination by membrane distillation, Int. J. Eng.
    Sci. Technol., 7 (2015) 267–278. 
-  H. Tekin, O. Bilkay, S.S. Ataberk, T.H. Balta, I.H. Ceribasi, F.D.
    Sanin, F.B. Dilek, U. Yetis, Use of Fenton oxidation to improve
    the biodegradability of a pharmaceutical wastewater, J. Hazard.
    Mater., 136 (2006) 258–265. 
-  S. Nachiappan, K. Muthukumar, Treatment of pharmaceutical
    effluent by ultrasound coupled with dual oxidant system,
    Environ. Technol., 34 (2013) 209–217. 
-  M.I. Badawy, R.A. Wahaab, A.S. El-Kalliny, Fenton biological
    treatment processes for the removal of some pharmaceuticals
    from industrial wastewater, J. Hazard. Mater., 167 (2009)
    567–574. 
-  S. Ishak, A. Malakahmad, Optimization of Fenton process for
    refinery wastewater biodegradability augmentation, Korean J.
    Chem. Eng., 30 (2013) 1083–1090. 
-  R.K. Tewari, F. Hadacek, S. Sassmann, I. Lang, Iron deprivationinduced
    reactive oxygen species generation leads to nonautolytic
    PCD in Brassica napus leaves, Environ. Exp. Bot., 91
    (2013) 74–83. 
-  J.M. Burns, P.S. Craig, T.J. Shaw, J.L. Ferry, Multivariate
    examination of Fe(II)/Fe(III) cycling and consequent hydroxyl
    radical generation, Environ. Sci. Technol., 44 (2010) 7226–7231. 
-  J.L. Pierre, M. Fontecave, Iron and activated oxygen species in
    biology: the basic chemistry, Biometals, 12 (1999) 195–199. 
-  Y.H.P. Hsieh, Y.P. Hsieh, Kinetics of Fe(III) reduction by
    ascorbic acid in aqueous solutions, J. Agric. Food Chem., 48
    (2000) 1569–1573. 
-  X. Hou, W. Shen, X. Huang, Z. Ai, L. Zhan, Ascorbic acid
    enhanced activation of oxygen by ferrous iron: a case of aerobic
    degradation of rhodamine B, J. Hazard. Mater., 308 (2016)
    67–74. 
-  H. Nakajima, A.M.M. Martínez, E.M.E. Silva, Mass Transfer –
    Advances in Sustainable Energy and Environment Oriented
    Numerical Modeling, InTech Chapters, 2013, pp. 387–388. 
-  S. Nachiappan, K.P. Gopinath, Treatment of pharmaceutical
    effluent using novel heterogeneous fly ash activated persulfate
    system, J. Environ. Chem. Eng., 3 (2015) 2229–2235. 
-  APHA, American Public Health Association, American Water
    Works Association, Water Pollution Control Federation,
    Standard Methods for the Examination of Water and Wastewater
    20, 1998. 
-  S. Nachiappan, K. Muthukumar, Intensification of textile
    effluent chemical oxygen demand reduction by innovative
    hybrid methods, Chem. Eng. J., 163 (2010) 344–354. 
-  F. Haber, J. Weiss, Uber die Katalyse des Hydroperoxydes
    (On the catalysis of hydroperoxide Naturwissenschaften), Die
    Naturwissenschaften, 20 (1932) 948–950. 
-  M.D. Paciolla, S. Kolla, S.A. Jansen, The reduction of dissolved
    iron species by humic acid and subsequent production of
    reactive oxygen species, Adv. Environ. Res., 1 (2002) 169–178. 
-  P. Belanzoni, L. Bernasconi, E.J. Baerends, O2 activation in a
    dinuclear Fe(II)/EDTA complex: spin surface crossing as a route
    to highly reactive Fe(IV)oxo species, J. Phys. Chem. A, 113
    (2009) 11926–11937. 
-  D.F. Laine, A. Blumenfeld, I.F. Cheng, Mechanistic study of the
    ZEA organic pollutant degradation system: evidence for H2O2,
	  HOo, and the homogeneous activation of O2 by FeIIEDTA, Ind.
    Eng. Chem. Res., 47 (2008) 6502–6508. 
-  L. Chen, J. Ma, X. Li, J. Zhang, J. Fang, Y. Guan, P. Xie, Strong
    enhancement on Fenton oxidation by addition of hydroxylamine
    to accelerate the ferric and ferrous iron cycles, Environ. Sci.
    Technol., 45 (2011) 3925–3930. 
-  Y. Li, T. Zhu, J. Zhao, B. Xu, Interactive enhancements of ascorbic
    acid and iron in hydroxyl radical generation in quinone redox
    cycling, Environ. Sci. Technol., 46 (2012) 10302–10309. 
-  N.K. Daud, B.H. Hameed, Decolorization of acid red 1 by
    Fenton-like process using rice husk ash-based catalyst, J.
    Hazard. Mater., 176 (2010) 938–944. 
-  N.C. Panja, R.D. Phaneswara, Measurement of gas–liquid
    parameters in a mechanically agitated contactor, Chem. Eng. J.,
    52 (1993) 121–129. 
-  T.J. Lin, K. Tsuchiya, L.S. Fan, Bubble flow characteristics in
    bubble columns at elevated pressure and temperature, AIChE
    J., 44 (1998) 545–560. 
-  Y. Weiguo, W. Jinfu, J. Yong, Gas-liquid mass transfer in a
    slurry bubble column reactor under high temperature and high
    pressure, Chin. J. Chem. Eng., 9 (2001) 253–257. 
-  S. Nachiappan, K. Muthukumar, Treatment of pharmaceutical
    effluent by sono-Fenton-sorption, Clean Soil Air Water, 42
    (2014) 1526–1533.