ABSTRACT
Phthalate esters (PAEs) are known as esters of phthalic acid, which are commonly used as plasticizers in the plastic industry. Due to the lack of chemical bonding with the polymer matrix, these compounds are easily separated from plastic products and enter the environment. To investigate the growth of concentration of PAEs like DBP (Dibutyl phthalate), DEP (Diethyl phthalate), DMP (Dimethyl phthalate), DIBP (Diisobutyl phthalate), and TPMBP (tris(2-methylbutyl) phosphate) in different water sources, a study from January 01, 1976, to April 30, 2021, was implemented via a global systematic review plus meta-analysis in which, 109 articles comprising 4061 samples, 4 water types, and 27 countries were included. Between various types of water sources, river water and lake water were the most contaminated resources with PAEs. Among all studies of PAEs, DBP and DEP with the values >15,573 mg L-1 have the highest average concentration and TPMBP with the value 0.002885 mg L-1 has the lowest average concentration in water sources. The most contaminated water sources with PAEs were in Nigeria and the least contaminated was in China. Besides, Monte-Carlo simulation indicated that for DMP and DEP minimum values that are lower than the acceptable limit are generated. However, most of the population (>75 %) is at risk for both adults and child cases. For DIBP and DBP the situation is much worse, the simulations not providing at least one case where the R index is lower than the acceptable limit of 1E-06.
ABSTRACT
This study aims to investigate the sonocatalytic activation of hydrogen peroxide (H2O2) using Cr2AlC MAX phase prepared by the reactive sintering process. The hexagonal structure of the crystalline MAX phase was confirmed by X-ray diffraction. Moreover, the compacted layered structure of the MAX phase was observed via scanning electron microscopy and high-resolution transmission electron microscopy. Under the desired operating conditions, Cr2AlC MAX phase (0.75 g/L) showed suitable potential to activate H2O2 (1 mmol/L) under sonication, thereby allowing a considerable removal efficiency for various organic pollutants, including dimethyl phthalate (69.1%), rifampin (94.5%), hydroxychloroquine (100%), and acid blue 7 (91.5%) with initial concentration of 15 mg/L within 120 min of treatment. Kinetic analysis proved that the degradation reaction followed pseudo-first-order kinetics. Scavenging tests demonstrated that hydroxyl radicals and singlet oxygen were effective species during degradation. Furthermore, a probable mechanism for dimethyl phthalate degradation was suggested according to gas chromatography-mass spectroscopy and nuclear magnetic resonance analyses. The obtained results confirmed the capability of the triple Cr2AlC/H2O2/US process as a promising method for treating contaminated water.
ABSTRACT
Organophosphate esters (OPEs) are used as additives in various industries. They do not chemically bond with the polymeric structure of materials, so they can stay for a long time and have a very adverse effect on the environment. To analyze the development of the prevalence and concentration of OPEs such as TCEP, TCPP, TDCP, TnBP, TPHP, TBOEP, TEHP, TMP, TCIPP, TDCIPP, TMPP, and TDBPP in water resources, a search between January 01, 2000, to April 08, 2021, was followed by a systematic review and meta-analysis. Among of the 888 articles scanned in the identity step, 58 articles containing 2676 samples, 10 countries, and 4 water types were included in the meta-analysis study. Among all studied OPEs, the concentration of TcrP, TCPP, TDCPP, and TnBP were at the top in water resources, with values >715 µg L-1 and lowest average concentrations were obtained for TDBPP and TpeP with values <0.0004 µg L-1. The most polluted area in terms of the concentration of OPEs in water resources was China. Besides, data analysis showed that there only was carcinogenic risk for China. A Monte-Carlo simulation indicated that although these obtained averages are in the same order of magnitude as the acceptable limit, for both adults and children, 95% of the population is at risk.
