The question is quite broad so the answer would be both yes and no.

It is possible to degrade many of the organic molecules measured by the COD, BOD etc. in the presence of e.g. Fe(III), SO42-, NO3-, Cl- and NH3 but e.g. NO2-, HS-, HCO3- interferes significantly with AOP oxidation of organic molecules.  

Dear Prof.Hendrick Rasmus Anderson,

Thanks for your response to my query. And my question is when we treat the inorganic-rich wastewater the oxidation potential given by the catalyst (via direct oxidation or by the formation of intermediate radicals) can be taken maximum by the inorganic species rather than the organic compounds. Hence, the removal percentage of COD, TOC will be low.  

For example, I was attempted many times to treat inorganic-rich wastewater streams (have appreciable COD) which contain Fe, Cl, Cu, Cr., But none of the time the treatment was not satisfied ( may be removal more than 80%) because the usage of catalyst and the unit operations was more in numbers.

In that case, the inorganic species may oxidize like Fe2+ to Fe3+ , Cr3+ to Cr6+and 2Cl- to Cl2 by taken the oxidation potential given by the catalyst. This case is not in account when they are in minimum concentrations. But, if they are in maximum concentrations (more than 10% of wastewater components), it makes the problem.

Hence, I think that if the catalyst/methods available which are more specific to the oxidation of organic species rather than inorganic compounds, it will be very useful to treat the inorganic-rich wastewater streams contain high composition in metal ions, TDS ( Cl or sulfate) and alkalinity.

So, I want to know any available treatment methodologies will address this issue in future. And I believe that my question is understand for you.

Thanks and Regards,

Maharaja.P

Dear Pounsamy,

It is difficult to answer as long as the question is very broad. Some people define AOPs solely as processes that work through HO· reactions. In this case it is difficult to find a process that has a variable reactivity to inorganic ions. If you take the broader definition you can get more selectivity from reactions that involve sulfate radicals (UV/PS, figure 3 in Maria Antoniou paper), ClO2, ozone and possible Cl· from UV/Cl2. 

I think a novel and very interesting process for selective reactions is the hydrated electrons generated by UV/SO32- and gamma radiation. 

You can find very fine work on both sulfate radicals and hydrated electrons in Prof. Sayeds recent publications.

Article Comparison of UVC/S2O82− with UVC/H2O2 in terms of efficienc...

Dear Prof.Murtaza Sayed and Prof.Henrik Andersen,

Thank you for your valuable comments and your mentioned references. I believe that they bring some idea about the oxidation of organics in the presence of inorganic species.

It may interest to generate hydrated electrons from the UV/SO32- and gamma radiation for the selective oxidative degradation of organic compounds. But the range of specificity of the hydrated electron is questionable.

Thanks and regards,

Maharaja.P