Hi Anshul,

Please check the following links and pdf attachments for the said query.

http://www.itrcweb.org/miningwaste-guidance/to_electrocoagulation.htm

http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4624377/

Best of Luck

Dear Ansul

pH is much depend the type of affluent and type of industries. It is also depend on type of electrode use and amount of dilution. The various parameter like DO, BOD , COD, Solids,Turbidity, Phenol, Phosphate and heavy metals.

This will also  help you

http://www.electrochemsci.org/papers/vol10/100604495.pdf

Reagards

Arvind

Dear Anshul Choubey,

It is commonly used to adjust the water to pH between 9-11 for the removal of heavy metals in general and Cd ions in particular, since in this pH range cadmium cation will form cadmium hydroxide which is precipitated and removed.

The following text is a concise summary of a review article which describes the removal of heavy metals including cadmium ions.

The conventional processes for removing heavy metals from wastewater include many processes such as chemical precipitation, flotation, adsorption, ion exchange, and electrochemical deposition. Chemical precipitation is the most widely used for heavy metal removal from inorganic effluent. The conceptual mechanism of heavy metal removal by chemical precipitation is presented in Eq. (1) Wang et al., 2004:

M2++2(OH) −↔M(OH ) 2↓

where M2+ and OH− represent the dissolved metal ions and the precipitant, respectively, while M(OH)2 is the insoluble metal hydroxide. Adjustment of pH to the basic conditions (pH 9–11) is the major parameter that significantly improves heavy metal removal by chemical precipitation

http://www.sciencedirect.com/science/article/pii/S1878535210001334

http://www.ucd.ie/dipcon/docs/theme08/theme08_07.PDF

A relatively new method (Cementation) for the removal of cadmium ions is desribed in the following text:

Cementation represents one of the most powerful techniques for removing heavy metals from wastewater. It consists in displacing the toxic metal ions from the waste solution by a more active nontoxic metal, for instance, Cd++ can be removed from

wastewater by cementation on zinc according to the reaction:

Zn + Cd++ = Zn++ + Cd        ne=2

http://pierre.fkit.hr/hdki/cabeq/pdf/17_3_2003/Cabeq%202003-03_7.pdf

Hoping this will be helpful,

Rafik

Hi Anshul,

pH in wastewater always affect the treatment process. in electrocoagulation process it will depend on the type of wastewater that your going to treat. say for example the wastewater from textile industries normally have pH higher than 8.5. Since this pH is in alkaline condition,  for metal precipitation using electrocoagulation this will be an ideal pH. Remember that in electrocoagulation process, resembles coagulation in cathode which produces OH- that reacts with metals released in anode. By this process it will promote coagulation and neutralization in any surface charge of ionic species on wastewater.

Thanks & Br,

Yes

Hi Anshul

Yes, pH of wastewater affects the performance of EC. It mostly depends on the type of wastewater you are dealing with by usually, EC works well in pH range of 6 to 8 and this range can be expanded to the range of 4 to 10 depending on the chemistry of your wastewater. In other words, the pH of the wastewater has effects on the solubility of the Metal Hydroxide generated by your EC cell which is going to act as the coagulant. Attached is the solubility diagram of Aluminum Hydroxide over the pH range. 

Cheers,

Armin

Would like to hear from anyone having experience or opinion and tried killing iron bacterias at alkaline pH using Ca-Mg carbonate or magnesite pellets.  Would think iron bacterias living in an acid climate, and spreading dolomitic material on the grass several times a year would increase the pH to around 8 or better, thus affecting the survival of  bacterias.  Is this correct thinking.  Looking for proper solution to control the presence of iron hydroxyde bacterias in French drain around the basement walls.  My theory is based upon mine acid drainage generation conditions.

thanks Raymond

It will determine the ionic characteristic of the metal hydroxides and dye molecules in solution and hence it will have a significant impact on the dye removal mechanism.

The Fe electrodes released ferrous (Fe2+) ions during electrolysis that could react with the HO− produced in the cathode to form Fe2+hydroxo complexes with hydroxide ions and polymeric species. Based on the Pourbaix diagram, complexes of Fe(OH)n were formed, and the majority were Fe(OH)2+ and Fe(OH)2+ for pH conditions ranging between 5 and 10.

Higher efficiencies using aluminium electrodes in EC technique were reached in 5–9 pH range which is close to the optimal pH for AI(OH)3(s) solid formation. The flocs of Al(OH)3(s) have large surface areas, which are useful for a rapid adsorption of soluble organic compounds and trapping of colloidal particles.