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Endocrine disrupting chemicals (EDCs) can cause adverse health effects in reproductive, neurological and immune systems, both on wildlife and on humans. EDCs may enter the environment from a variety of sources: run-off from agricultural lands, leakage from septic tanks, sewage treatment plants (STP) … Despite are usually present at trace concentrations, EDCs can still cause significant serious damage. Worldwide EDCs release constantly increases, and it has been demonstrated that the efficiency of conventional water treatment technologies against these contaminants is very limited. Advanced oxidation processes (AOPs) constitute a promising technology for removal of most persistent organic pollutants (POPs), such as EDCs, from waters, and among AOPs, photocatalytic methods are likely the most promising, specially those involving Vis light responsive materials, i.e. solar heterogeneous photocatalysis. This review provides a general and critical overview of the most recent state-of-the-art research on the photocatalytic degradation of EDCs over the last two years. We start describing briefly the problems posed by EDCs in the environment and the fundamentals of photocatalysis, and then focus on the degradation of EDCs in the presence of photocatalysts under irradiation.

To assess the potential use of two montmorillonite‐(cerium [Ce] or zirconium [Zr]) phosphate crosslinked compounds in removing organic pollutants from water, the adsorption of atrazine (6‐chloro‐N2‐ethyl‐N4‐isopropyl‐1,3,5‐triazine‐2,4‐diamine) and one of the major metabolites of atrazine in water, deisopropylatrazine (6‐chloro‐N4‐ethyl‐1,3,5‐triazine‐2,4‐diamine), has been studied at 25°C using batch experiments. The influence of the presence of 0.01 MKCl in the medium was also investigated for a better understanding of variables affecting the adsorption of these organic compounds. Experimental data points have been fitted to the Langmuir equation, with the results indicating a higher adsorption for deisopropylatrazine than for atrazine on both adsorbents in saline and nonsaline medium. Variation of the uptake of atrazine and the metabolite in the solution of 0.01 MKCl shows an enhanced adsorption of deisopropylatrazine on both samples compared w th that of atrazine. Fourier‐transformed infrared (FTIR) spectroscopic studies reveal that at the pH generated by the adsorbents (3.7 and 3.9 for Ce and Zr—montmorillonite compounds, respectively), atrazine and its metabolite interact with the surface of the adsorbents. X‐ray diffraction analysis showed that the compounds studied are intercalated into the adsorbents. For the compounds considered, the cerium—montmorillonite adsorbent shows a higher capacity of adsorption compared with zirconium—montmorillonite adsorbent, so it might be particularly useful in removing atrazine and, to a greater extent, deisopropylatrazine from water.

The herbicides diuron [3‐(3,4‐dichlorophenyl)‐1,1‐dimethylurea] and atrazine [6‐chloro‐N2‐ethyl‐N4‐isopropyl‐1,3,5‐triazine‐2,4‐diamine] were incorporated in alginate‐based granules to obtain controlled release (CR) properties. The basic formulation [sodium alginate (14.0 g kg−1)‐herbicide(6.0 g kg−1)‐water] was modified by addition of sorbents. The effect on (Huron and atrazine release rate, caused by incorporation of natural bentonite and humic acid in the alginate formulation, was studied by immersion of the granules in water under static conditions. The release of the active ingredient from alginate‐based CR granules in water was affected by the addition of natural bentonite, and to a greater extent, by the addition of the humic acid. The water uptake, permeability, and the time taken for 50% of active ingredient to be released into water, T50, were calculated for the comparison of the preparations. Addition of both bentonite and humic acid samples to the basic alginate‐based formulation produced the higher T50values (43.11 and 50.49 d for diuron and atrazine formulations, respectively), indicating a slower release of herbicide. Based on parameters of an empirical equation used to fit the herbicide release data, it appears that the release of diuron and atrazine from the various formulations into water is controlled by a diffusion mechanism. Sorption capacity of the sorbent and the permeability of the formulations (ranging from 3.77 to 20.83 mg d−1mm−1) were the most influential factors affecting herbicide release.

In order to prepare a formulation to be used for controlled release, imidacloprid was incorporated into alginate granules by using calcium chloride as gellant. The formulation prepared (alginate–imidacloprid–water) was modified by the addition of different sorbents. The effects on release rate of the addition of natural bentonite desiccated at 105 °C, untreated, acid-treated with sulfuric acid solutions over a concentration range between 0.5 mol dm⁻³ and 2.5 mol dm⁻³, and a commercial humic acid, were studied by immersion of the granules in water under static conditions. The time taken for 50% of the active ingredient to be released into water, (T50), was calculated from the data obtained. On the other hand, the sorption–desorption processes of imidacloprid from a 0.01 M aqueous calcium chloride solution at 25 °C, by natural, acid-treated bentonite samples, and humic acid, have been studied by using batch experiments in order to evaluate the potential of these materials for their application in controlled-release formulations of pesticides. The experimental data have been fitted to the Freundlich equation in order to calculate the adsorption capacities (Kf). Kf values ranged from 1.76 mg kg⁻¹ for the untreated bentonite up to 126.9 mg kg⁻¹ for the humic acid. A correlation study was performed with T50, the surface area (S) and the Freundlich parameter (Kf) of the bentonite samples in order to know the factors that affect release rate of imidacloprid from bentonite granules. A linear correlation of the T50 values and both S and Kf parameters was observed. © 1999 Society of Chemical Industry

The mobility of imidacloprid [1-(6-chloro-3-pyridinyl)methyl]-N-nitro-2-imidazolidinimine] from alginate-based controlled-release (CR) formulations was investigated in two different soil profiles. In one, a layered bed system simulating the typical arrangement under a plastic greenhouse, which is composed of sand, peat, amended soil and native soil, was used. In the other, the layer containing amended soil was used in order to determine the mobility of the insecticide in a soil system with a low content of organic matter and a high content of clay. Two CR formulations based on sodium alginate (1.87% wt/wt), imidacloprid (1.21%), natural or acid-treated bentonite (3.28%), and water (93.64%) were compared to technical grade imidacloprid. The use of alginate CR formulations produced less vertical mobility of the active ingredient as compared to the technical product. With the technical grade product treatment, the total amount of imidacloprid leached from columns packed with amended soil was 82.3% of that applied, whereas for the alginate-based CR formulations containing natural or acid-treated bentonite, the leached percentages were 44.7% and 37.1%, respectively. In the column experiments simulating the layered bed system, no insecticide was found in the leachate when the alginate-based CR formulations containing natural bentonite were used. However, 3% of the applied imidacloprid appeared when the treatment was carried out with technical grade material. Sorption-desorption capacities of the various soil layers for imidacloprid molecules were also calculated using batch experiments. © 1999 Society of Chemical Industry

Sepiolite is a hydrated magnesium silicate clay with a fibrous structure and binder properties. To calculate the potential use of sepiolite in removing atrazine [2-chloro-4-ethylamino-6-isopropilamino-1,3,5,-triazine], isoproturon [3-(4-isopropylphenyl)-1,1-dimethylurea] and imidacloprid [1-(6-chloro-3-pyridinylmethyl)-N-nitroimidazolin-2-ylideneamine] from water, the adsorption of atrazine, isoproturon and imidacloprid on sepiolite desiccated at 110 °C from aqueous solution at 25 °C has been studied by using batch experiments. In addition, column experiments were carried out with the sepiolite sample using aqueous solutions of atrazine, isoproturon and imidacloprid at a concentration of 20.0 × 10⁻⁴ cmol dm⁻³. The experimental data points have been fitted to the Langmuir equation to calculate the adsorption capacities (Xm). Values for Xm ranged from 2.70 × 10⁻¹ cmol kg⁻¹ for isoproturon up to 3.97 × 10⁻¹ cmol kg⁻¹ for atrazine. The removal efficiency (R) ranged from 36.7% for isoproturon up to 74.3% for atrazine. The batch experiments show that the sepiolite is more effective in adsorbing atrazine than imidacloprid and isoproturon. The column experiments show that sepiolite might be reasonably used in removing atrazine, the column efficiency being 46%. The data indicate that a readily available and inexpensive Spanish sepiolite can be employed as a filter for contaminated waters with these pesticides, controlling their release to the environment. © 1999 Society of Chemical Industry

The sorption of linuron on bentonite desiccated at 110°C untreated, and acid-treated with H2SO4 solutions over a concentration range between 0.25 M and 1.00 M from aqueous solution at 25°C has been studied by using batch experiments. In addition, column experiments were carried out with the bentonite sample treated with the 1.00 M H 2SO4 solution [B-A(1.00)] by using two aqueous solutions of linuron of different concentrations (C=4.97 mg dm⁻³ and C=7.63 mg dm⁻³ ). The experimental data points have been fitted to the Langmuir equation in order to calculate the sorption capacities (Xm) of the samples; Xm values range from 0.02 g kg⁻¹ for the untreated bentonite [B-N] up to 0.20 g kg⁻¹ for the sample acid-treated with the 1.00 M H2 SO4 solution. The removal efficiency (R ) has also been calculated; R values ranging from 15.86% for the [B-N] sample up to 41.54% for [B-A(1.00)]. The batch experiments show that the acid-treated bentonite is more effective than the natural bentonite in relation to sorption of linuron. The column experiments show that the B-A(1.00) sample might be reasonably used in removing linuron, the column efficiency increasing from 61.8% for the C=7.63 mg dm⁻³ aqueous solution of linuron up to 77.6% for the C=4.97 mg dm⁻³ one. © 1999 Society of Chemical Industry

To evaluate the potential use of bentonite in removing atrazine [2‐chloro‐4‐ethylamino‐6‐isopropilamino‐1,3,5‐triazine] from water, the adsorption of atrazine on bentonite desiccated at 383 K untreated, and acid‐treated with H2SO4solutions over a concentration range between 0.25 × 103cmol L−1and 1.00 × 103cmol L−1, from aqueous solution at 303 K has been studied by using batch experiments. In addition, column experiments were carried out with the bentonite samples treated with the 1.00 × 103cmol L−1H2SO4[B‐A (1.00)] using two aqueous atrazine solutions at C= 5.91 mg L−1and C= 9.78 mg L−1concentrations. The experimental data points have been fitted to the Langmuir equation to calculate the adsorption capacities (Xm). Values for Xmranged from 0.07 g kg−1for the untreated bentonite up to 13.4 g kg−1for the [B‐A (1.00)] samples. The removal efficiency (R) ranged from 2.71% for the B‐N up to 83.5% for B‐A (1.00). The batch experiments show that the acid‐treated bentonite is more effective than the natural bentonite in relation to the adsorption of atrazine. The column experiments show that the B‐A (1.00) sample might be reasonably used in removing atrazine, the column efficiency increasing from 47.5% for the C= 9.78 mg L−1aqueous solution of atrazine up to 63.4% for the C= 5.91 mg L−1one.