Although the classical Fenton process exhibits a high initial rate of the organic compounds degradation, this process is not complete due to the formation of refractory compounds which resist the attack of the hydroxyl radicals. In the presence of Cu(II), the degradation is slower, but results in a greater reduction of TOC (total organic carbon) measurements of net mineralization at the end of the reaction (t=120min). The addition of Cu(II) ions to classical Fenton reaction conditions (Fe(II) plus H2O2 at pH 3) is shown to accelerate the degradation of organic compounds. This synergic effect causes an approximately 15% additional reduction of the TOC. Voltammetric studies confirm the catalytic role of catechol in the presence of Fe(III)/Fe(II) and Cu(II)/Cu(I). Addition of aliphatic acids to the reaction medium, did not interfere with the cupro-Fenton reaction, but had an inhibitory effect on the classical Fenton reaction, consistent with the following order of interaction with the ion Fe(III): Oxalic Acid (OA) >> Formic Acid (FA) ~ Acetic acid (AA).

Números de agregação (N Ag) de micelas do detergente aniônico lauril éter sulfato de sódio (SLES), com duas subunidades de óxido de etileno, foram determinados a 30 e 40º C por supressão de fluorescência resolvida no tempo, utilizando pireno como sonda fluorescente e o íon N-hexadecilpiridíneo como o supressor. O crescimento das micelas de SLES induzido por sal (γ = 0,11-0,15, sendo γ a inclinação de um gráfico do log do número de agregação vs. log [Yaq] e [Yaq] a concentração de contraíons sódio livres na fase aquosa intermicellar) é significativamente menor do que o de micelas de alquilsulfato de sódio (γ ca. 0,25), uma diferença atribuída ao tamanho maior do grupo polar de SLES. A razão de intensidades vibrônicas I1/I3 e a constante de velocidade para a supressão intramicelar do pireno demonstram que a polaridade do microambiente de solubilização e a viscosidade intramicelar são insensíveis ao tamanho da micela ou à presença de sal.

Aggregation numbers (N Ag) of micelles of the commercial anionic detergent sodium lauryl ether sulfate (SLES), with an average of two ethylene oxide subunits, were determined at 30 and 40º C by the time-resolved fluorescence quenching method with pyrene as the fluorescent probe and the N-hexadecylpyridinium ion as the quencher. The added-salt dependent growth of SLES micelles (γ = 0.11-0.15, where γ is the slope of a plot of log aggregation number vs. log [Yaq] and [Yaq] is the sodium counterion concentration free in the intermicellar aqueous phase) is found to be significantly lower than that of sodium alkyl sulfate micelles (γ ca. 0.25), a difference attributed to the larger headgroup size of SLES. The I1/I3 vibronic intensity ratio and the rate constant for intramicellar quenching of pyrene show that the pyrene solubilization microenvironment and the intramicellar microviscosity are insensitive to micelle size or the presence of added salt.