Use of Novel Cardanol-Porphyrin Hybrids and Their TiO2-Based Composites for the Photodegradation of 4-Nitrophenol in Water

Abstract

Cardanol, a well known hazardous byproduct of the cashew industry, has been used as starting material for the synthesis of useful differently substituted “cardanol-based” porphyrins and their zinc(II), copper(II), cobalt(II) and Fe(III) complexes. Novel composites prepared by impregnation of polycrystalline TiO2 powder with an opportune amount of “cardanol-based” porphyrins, which act as sensitizers for the improvement of the photo-catalytic activity of the bare TiO2, have been used in the photodegradation in water of 4-nitrophenol (4-NP), which is a toxic and bio-refractory pollutant, dangerous for ecosystems and human health.

Cashew Nut Shell Oil — A Renewable and Reliable Petrochemical Feedstock

“…The porphyrins are brown-red sticky solids, very soluble in CHCl 3 or CH 2 Cl 2 [32]. This substituted cardanolbased porphyrin and their metallic complexes have been used extensively in photo degradation of toxic, bio-refractory 4-nitro phenol in water, which is dangerous for the ecosystem and for human health [32]. CNSL is also useful in fuel blends and fuel mixtures [33] and for producing diesel oil [34].…”

Synthesis, Characterization and Dielectric Properties of New 5-(4-Hydroxyphenyl)-10,15,20-tri-4-[2-(3-pentadecylphenoxy)ethoxy]phenyl porphyrin and Their Ni, Co and Cu Complexes

“…The synthesis of porphyrins starting from cardanol are mentioned by many papers since 2004, [26][27][28][29] and they employed a procedure which consists in producing an aldehyde derivative as precursor. Normally, this precursor is compound 3 (4-[2-(3-pentadecylphenoxy) ethoxy] benzaldehyde), obtained by a reaction between compound 2 (1-(2-bromoethoxy)-3-pentadecylbenzene) and 4-hydroxybenzaldehyde in acetone using anhydrous potassium carbonate (K 2 CO 3 ) as base, stirred for 24 h and with 40% yield.…”

Electrooxidation of cardanol on mixed metal oxide (RuO2-TiO2 and IrO2-RuO2-TiO2) coated titanium anodes: insights into recalcitrant phenolic compounds

“…Cardanol (CDN) is the major by-product from cashew-nut processing and arising from the thermal decomposition of anacardic acid [7][8][9]. It is indeed a mixture of both Z and E isomers of one long alkyl-chain attached to the phenolic ring, which differs in the unsaturation degree [10] (see Figure 1).…”

“…However, the industrial production also generates a massive amount of caustic, viscous and harmful residues, containing a mixture of saturated and unsaturated meta-alkylphenols with strong amphiphilic character [6][7][8]. The high stability [7] and toxicity [9] of these compounds represent a threat to the environment if the wastewaters containing them do not receive a suitable pre-treatment before the final disposal. Biological treatment is the most employed around the world for this kind of effluents, however, several studies have showed that it is inefficient to remove recalcitrant organic compounds [1,[3][4][5].…”

“…These same authors still complemented that monounsaturated cardanol 3-(pentadeca-8-enyl)phenol holds the largest percentage (24.28%). According to Vasapollo and co-workers [9], the monounsaturated cardanol is the main derivative (80%) after the purification of the cashew-nut shell liquid by vacuum distillation, followed by other saturated (8% of 3-n-pentadecylphenol) and unsaturated (8% of 3-(pentadeca-8,11-dienylphenol and 6% of 3-(pentadeca-8,11,14-trienyl)phenol) cardanols. In the industrial wastewaters, these compounds present low purity and the recuperation processes are expensive with lower yields [11].…”