Advanced treatment of phenol by H₂O₂/UV/activated carbon coupling: Influence of homogeneous and heterogeneous phase

Abstract

In this work, a heterogeneous catalytic wet peroxide process combining activated carbon (AC) and hydrogen peroxide (H 2 O 2 )/ultraviolet radiation was applied for the aqueous-phase removal of phenol. The influence of the pH and peroxide concentration were determined according to a factorial plan. The kinetic contribution of radical mechanisms (d HO8 ) was estimated using a radical scavenger (tert-butyl alcohol). The degradation kinetics was modelled by a global pseudo-first-order kinetic model based on the sum of the effects during the treatment process. The results showed that these two variables significantly affected the percentage removal. The peroxide concentration exerted a positive effect (i.e., as the H 2 O 2 concentration increased, the percentage removal also increased). Additionally, as the pH value increased, the degradation accelerated, and the kinetic constant (k homogeneous ) increased from 0.00938 min À1 to 0.02772 min À1 . The results obtained in the presence of AC demonstrated the ability of AC to ameliorate the degradation of phenol; for example, d heterogeneous was 45.69 % to 41.35 %.

Low-cost activated carbon for adsorption and heterogeneous ozonation of phenolic wastewater treatment

“…Therefore, to better understand the mechanisms involved and in order to compare ozonation processes and adsorption under the same conditions, the kinetic study was performed on the first 5 min. As in the other studies in the literature [17,21,22,24], it was figured that the catalytic ozonation could be the result of five mechanisms. Each one was identified with its kinetics law and the simplified global kinetic law can be obtained by summing all the kinetic laws.…”

“…The removal process of the contaminant can take place in the bulk phase (homogeneous oxidation) and/or at the AC surface. In so doing, AC may act as an adsorbent and/or as an initiator of free radicals [20,21]. The AC physico-chemical properties were found to influence the decomposition of O 3 on AC: Sánchez-Polo et al [22] and Alvárez et al [23] evidenced the importance of the specific surface, the mesoporous volume and the presence of basic groups at the surface of the AC.…”

Sustentabilidade agroindustrial: Processos Oxidativos Avançados (POA) utilizando bioadsorventes brasileiros

“…Alguns autores também obtiveram resultados semelhantes utilizando POA/AC onde uma quantidade maior de funções tanto ácidas (Valdés e Zaror, 2006) como básicas (Sanchez-polo et al, 2005 podem aumentar a interação do CA com o agente oxidante aumentando desta forma a geração de radicais hidroxilas •OH (Flouret at al., 2018;Oliveira et al, 2011;).…”

“…Entre estes processos destacam-se os Processos Oxidativos Avançados (POA's), capazes de gerar radicais hidroxila em quantidades suficientes para oxidar as substâncias químicas presentes em efluentes. Os POA's são oferecidos como uma alternativa aos métodos de oxidação convencionais e são baseados na geração de radicais hidroxila (• OH) (Flouret et al, 2018) e demonstram ser métodos de tratamento eficazes para degradar materiais persistentes quando os tratamentos convencionais não atingem a eficácia necessária. Estes processos podem ser heterogêneos ou homogêneos, e utilizar ou não a radiação UV (Habib et al, 2020).…”

Adsorção do dietil ftalato (DEP) em carvão ativado (CA) de casca de coco verde: caracterização físico-química e influência dos parâmetros operacionais

“…Todas as análises foram realizadas em triplicata. As funções ácido foram determinadas utilizando soluções de NaHCO3, Na2CO3 e NaOH (0,02 mol L -1 ) em excesso e foram tituladas com uma solução de HCl (0,02 mol L -1 ) (Oliveira et al, 2011a;2011b;Flouret et al, 2018).…”