In dilute buffer solutions, cyclic voltammograms (CVs) of hydroquinone (QH 2 ) and quinone (Q) depends on the buffer capacity (β). The explanation is that the pH changes at the electrode surface cause the electrochemical redox rates of QH 2 and Q rapidly decline and new peaks occur. An electrochemical approach has been developed for measuring β, which requires the introduction of QH 2 or Q into the solution instead of a strong acid or base. Therefore, the approach has potential for measuring the intracellular βi without interference from proton transportation. The approach was successfully applied to measure the β of human saliva.

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In the simultaneous flue gas desulfurization and denitrification by biological combined with chelating absorption technology, SO 2 and NO are converted into sulfate and Fe(II)EDTA-NO which need to be reduced in biological reactor. Increasing the removal loads of sulfate and Fe(II)EDTA-NO and converting sulfate to elemental sulfur will benefit the application of this process. A moving-bed biofilm reactor was adopted for sulfate and Fe(II)EDTA-NO biological reduction. The removal efficiencies of the sulfate and Fe(II)EDTA-NO were 96% and 92% with the influent loads of 2.88 kg SO 4 2− ·m −3 ·d −1 and 0.48 kg NO·m −3 ·d −1 . The sulfide produced by sulfate reduction could be reduced by increasing the concentrations of Fe(II)EDTA-NO and Fe(III)EDTA. The main reduction products of sulfate and Fe(II)EDTA-NO were elemental sulfur and N 2 . It was found that the dominant strain of sulfate reducing bacteria in the system was Desulfomicrobium. Pseudomonas, Sulfurovum and Arcobacter were involved in the reduction of Fe(II)EDTA-NO.