Multi-target assessment of advanced oxidation processes-based strategies for indirect potable reuse of tertiary wastewater: Fate of compounds of emerging concerns, microbial and ecotoxicological parameters

Two advanced oxidation processes (AOPs), namely ozone/H2O2 and UV/H2O2, were tested at pilot scale as zero-liquid-discharge alternative treatments for the removal of microbiological (bacteria and viruses), chemical (compounds of emerging concern (CECs)) and genotoxic responses from tertiary municipal wastewater for indirect potable reuse (IPR). The AOP treated effluents were further subjected to granular activated carbon (GAC) adsorption and UV disinfection, following the concept of multiple treatment barriers. As a reference, a consolidated advanced wastewater treatment train consisting of ultrafiltration, UV disinfection, and reverse osmosis (RO) was also employed. The results showed that, for the same electrical energy applied, the ozone/H2O2 treatment was more effective than the UV/H2O2 treatment in removing CECs. Specifically, the ozone/H2O2 treatment, intensified by high pressure and high mixing, achieved an average CECs removal efficiency higher than UV/H2O2 (66.8% with respect to 18.4%). The subsequent GAC adsorption step, applied downstream the AOPs, further improved the removal efficiency of the whole treatment trains, achieving rates of 98.5% and 96.8% for the ozone/H2O2 and UV/H2O2 treatments, respectively. In contrast, the ultrafiltration step of the reference treatment train only achieved a removal percentage of 22.5%, which increased to 99% when reverse osmosis was used as the final step. Microbiological investigations showed that all three wastewater treatment lines displayed good performance in the complete removal of regulated and optional parameters according to both national and the European Directive 2020/2184. Only P. aeruginosa resulted resistant to all treatments with a higher removal by UV/H2O2 when higher UV dose was applied. In addition, E. coli STEC/VTEC and enteric viruses, were found to be completely removed in all tested treatments and no genotoxic activity was detected even after a 1000-fold concentration. The obtained results suggest that the investigated treatments are suitable for groundwater recharge to be used as a potable water source being such a procedure an IPR. The intensified ozone/H2O2 or UV/H2O2 treatments can be conveniently incorporated into a multi-barrier zero-liquid-discharge scheme, thus avoiding the management issues associated with the retentate of the conventional scheme that uses reverse osmosis. By including the chemical cost associated with using 11-12 mg/L of H2O2 in the cost calculations, the overall operational cost (energy plus chemical) required to achieve 50% average CECs removal in tertiary effluent for an hypothetical full-scale plant of 250 m3/h (or 25,000 inhabitants) was 0.183 €/m3 and 0.425 €/m3 for ozone/H2O2 and UV/H2O2 treatment train, respectively.

Inherently Antimicrobial P(MMA-ran-DMAEMA) Copolymers Sensitive to Photodynamic Therapy: A Double Bactericidal Effect for Active Wound Dressing

In this work, two compounds belonging to the BODIPY family, and previously investigated for their photosensitizing properties, have been bound to the amino-pendant groups of three random copolymers, with different amounts of methyl methacrylate (MMA) and 2-(dimethylamino)ethyl methacrylate (DMAEMA) in the backbone. The P(MMA-ran-DMAEMA) copolymers have inherently bactericidal activity, due to the amino groups of DMAEMA and to the quaternized nitrogens bounded to BODIPY. Systems consisting of filter paper discs coated with copolymers conjugated to BODIPY were tested on two model microorganisms, Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus). On solid medium, irradiation with green light induced an antimicrobial effect, visible as a clear inhibition area around the coated disks. The system based on the copolymer with 43% DMAEMA and circa 0.70 wt/wt% of BODIPY was the most efficient in both bacterial species, and a selectivity for the Gram-positive model was observed, independently of the conjugated BODIPY. A residual antimicrobial activity was also observed after dark incubation, attributed to the inherently bactericidal properties of copolymers.

Meso- and Rac-[bis(3-phenyl-6-tert-butylinden-1-yl)dimethylsilyl]zirconium Dichloride: Precatalysts for the Production of Differentiated Polyethylene Products with Enhanced Properties

Ansa-zirconocene complexes are widely employed as precatalysts for olefin polymerization. Their synthesis generally leads to mixtures of their rac and meso isomers, whose separation is often problematic. In this contribution, we report on the synthesis of a novel silyl-bridged bis(indenyl)-based metallocene, and on the separation of its rac and meso isomers by simple recrystallization from toluene. The two complexes, activated by methylaluminoxane (MAO), have been used as precatalysts in ethylene/1-hexene copolymerization. Regardless of the reaction conditions, the meso complex outperformed its rac congener. A similar trend was observed by performing the process in the presence of the silica-supported versions of the complexes. This is remarkable, since meso metallocenes generally display lower activities than their rac analogues. Furthermore, the meso isomer generates polymer products that are more in line with the targets for the preparation of a bimodal PE grade made of a lower-MW high-density (HDPE) fraction and a higher-MW linear low-density (LLDPE) fraction.

Comparative assessment of marine weathering of ROP-derived biopolymers against conventional plastics

Bio-based plastics were designed to replace single-use plastics and to cause less post-consumer environmental damage. This paper assesses the weathering of four bio-based polymers created by ring opening polymerization (ROP) promoted by a previously reported Ti-based catalyst, to detect any problems before production was scaled up. Samples were aged in seawater to identify degradation products and monitor structural changes. Surfaces evidenced degradation and a range of leaching products was observed. Aside from compounds used in the preparation of the plastics (i.e. residual monomers and benzyl alcohol), the degradation products included carboxylic acids (often found in plastic leachate), oxacyclohexadecan-2-one (potentially toxic to aquatic life) and triphenylmethane (potential carcinogen). Overall, there were fewer structural changes in the fossil fuel based polymer (PS) and in the commercially available bio-based plastic studied for comparison purposes than the lab based bio-based polymers.

Scandium calix[n]arenes (n = 4, 6, 8): structural, cytotoxicity and ring opening polymerization studies

Interaction of [Sc(OR)3] (R = iPr or triflate) with p-tert-butylcalix[n]arenes, where n = 4, 6, or 8, affords a number of intriguing structural motifs, which are relatively non-toxic (cytotoxicity evaluated against cell lines HCT116 and HT-29) and a number were capable of the ring opening polymerization (ROP) of cyclohexene oxide.

Lithium calix[4]arenes: structural studies and use in the ring opening polymerization of cyclic esters

We have structurally characterized a number of lithiated calix[4]arenes, where the bridge in the calix[4]arene is thia (–S–, L^SH₄), sulfinyl (–SO–, L^SOH₄), sulfonyl (–SO₂–, L^SO2H₄), dimethyleneoxa (–CH₂OCH₂–, L^COCH₄) or methylene (–CH₂–, LH₄). In the case of L^4SH₄, interaction with LiOtBu led to the isolation of the complex [Li₈(L^4S)₂(THF)₄]·5THF (1·5THF), whilst similar interaction of L^4SOH₄ led to the isolation of [Li₆(L^4SOH)₂(THF)₂]·5(THF) (2·5THF). Interestingly, the mixed sulfinyl/sulfonyl complexes [Li₈(calix[4]arene(SO)(SO₂)(SO_1.68)₂)₂(THF)₆]·8(THF) (3·8THF) and [Li₅Na(L^SO/3SO2H)₂(THF)₅]·7.5(THF) (4·7.5(THF) have also been characterized. Interaction of LiOtBu with L^SO2H₄ and L^COCH₄ afforded [Li₅L^4SO2(OH)(THF)₄]·2THF (5·2THF) and [Li₆(L^COC)₂(HOtBu)₂]·0.78THF·1.22hexane (6·0.78THF·1.22hexane), respectively. In the case of LH₄, reaction with LiOtBu in THF afforded a monoclinic polymorph [LH₂Li₂(thf)(OH₂)₂]·3THF (7·3THF) of a known triclinic form of the complex, whilst reaction of the de-butylated analogue of LH₄, namely de-BuLH₄, afforded a polymeric chain structure {[Li₅(de-BuL)(OH)(NCMe)₃]·2MeCN}_n (8·2MeCN). For comparative catalytic studies, the complex [Li₆(L^Pr)₂(H₂O)₂]·hexane (9 hexane), where L^Pr2H₂ = 1,3-di-n-propyloxycalix[4]areneH₂, was also prepared. The molecular crystal structures of 1–9 are reported, and their ability to act as catalysts for the ring opening (co-)/polymerization (ROP) of the cyclic esters ε-caprolactone, δ-valerolactone, and rac-lactide has been investigated. In most of the cases, complex 6 outperformed the other systems, allowing for higher conversions and/or greated polymer M_n.

Novel Li-calix[n]arene complexes (n = 3, 4) having (–S–), (–SO–), (–SO₂–), (–CH₂OCH₂–) or (–CH₂–) bridges have been synthesized and fully characterized. Their catalytic activity in the ring opening polymerization of lactones has been studied.

INSIGHTS into the structures adopted by titanocalix[6 and 8]arenes and their use in the ring opening polymerization of cyclic esters

Interaction of p-tert-butylcalix[6]areneH6, L1H6, with [TiCl4] afforded the complex [Ti2Cl3(MeCN)2(OH2)(L1H)][Ti2Cl3(MeCN)3(L1H)]·4.5MeCN (1·4.5MeCN), in which two pseudo-octahedral titanium centres are bound to one calix[6]arene. A similar reaction but employing THF resulted in the THF ring-opened product [Ti4Cl2(μ3-O)2(NCMe)2(L)2(O(CH2)4Cl)2]·4MeCN (2·4MeCN), where LH4 = p-tert-butylcalix[4]areneH4. Interaction of L1H6 with [TiF4] (3 equiv.) led, after work-up, to the complex [(TiF)2(μ-F)L1H]2·6.5MeCN (3·6.5MeCN). Treatment of p-tert-butylcalix[8]areneH8, L2H8, with [TiCl4] led to the isolation of the complex [(TiCl)2(TiClNCMe)2(μ3-O)2(L2)]·1.5MeCN (4·1.5MeCN). From a similar reaction, a co-crystallized complex [Ti4O2Cl4(MeCN)2(L2)][Ti3Cl6(MeCN)5(OH2)(L2H2)]·H2O·11MeCN (5·H2O 11MeCN) was isolated. Extension of the L2H8 chemistry to [TiBr4] afforded, depending on the stoichiometry, the complexes [(TiBr)2(TiBrNCMe)2(μ3-O)2(L2)]·6MeCN (6·6MeCN) or [[Ti(NCMe)2Br]2[Ti(O)Br2(NCMe)](L2)]·7.5MeCN (7·7.5MeCN), whilst use of [TiF4] afforded complexes containing Ca2+ and Na+, thought to originate from drying agents, namely [Ti8CaF20(OH2)Na2(MeCN)4(L2)2]·14MeCN (8·14MeCN), [Na(MeCN)2][Ti8CaF20NaO16(L2)2]·7MeCN (9·7MeCN) or [Na]6[Ti8F20Na(MeCN)2(L2)][Ti8F20Na(MeCN)0.5(L2)]·15.5(C2H3N) (10·15.5MeCN). In the case of [TiI4], the ladder [(TiI)2(TiINCMe)2(μ3-O)2(L2)]·7.25CH2Cl2 (11·7.25CH2Cl2) was isolated. These complexes have been screened for their potential to act as catalysts in the ring opening polymerization (ROP) of ε-caprolactone (ε-CL), δ-valerolactone (δ-VL) and rac-lactide (r-LA), both in air and N2. For ε-CL and δ-VL, moderate activity at 130 °C over 24 h was observed for 1, 9 and 11; for r-LA, only 1 exhibited reasonable activity. In the case of the co-polymerization of ε-CL with δ-VL, the complexes 1 and 11 afforded reasonable conversions and low molecular weight polymers, whilst 4, 6, and 9 were less effective. None of the complexes proved to be active in the co-polymerization of ε-CL and r-LA under the conditions employed herein.

Controlling micropollutants in tertiary municipal wastewater by O3/H2O2, granular biofiltration and UV254/H2O2 for potable reuse applications

A comprehensive pilot study was carried out to experimentally assess the potential of newly developed treatment trains integrating two-stage AOPs and biofiltration to reach potable reuse water quality standards from municipal wastewater. The processes consisted of a two-stage AOPs with (carbon or limestone) biofiltration, the first AOP (O₃/H₂O₂) serving as pre-treatment to biofiltration and the second AOP (UV₂₅₄/H₂O₂) serving as post-biofiltration finishing step to ensure advanced disinfection. A comprehensive monitoring campaign was put in place resulting from the combination of targeted, non-targeted and suspect screening measurements. It was found that 13 organic micropollutants were detected from a list of 219 suspects although at ng/L level only. For the treatment conditions piloted in this study (O₃ = 13 ± 0.5 mg/L, H₂O₂ = 11 ± 0.4 mg/L for the O₃/H₂O₂ process, and UV = 410 ± 63.5 mJ/cm², H₂O₂ = 5 mg/l for the UV₂₅₄/H₂O₂ process), it was possible to estimate the overall removal efficacy for each unit process, which was found to follow this order: RO (99%)  > BAC (87%) > O₃-H₂O₂ (78%)  > BAL (67%)  > UV/H₂O₂ (43%)  > AOP contact chamber (19%)  > UF(0%), with the treatment train integrating two AOPs and granular biofiltration with activated carbon (O₃/H₂O₂ + BAC + UV₂₅₄/H₂O₂) showing superior performance with a 99% abatement in total micropollutants. No ecotoxicologically-positive response was generally observed for any of the effluent samples from the tested trains, even when pre-concentration factors up to 100-1000 times were employed to increase the sensitivity of the bioassay methods.

Use of titanocalix[4]arenes in the ring opening polymerization of cyclic esters

Titanocalix[4]arenes are shown to be active for the ROP of cyclic esters under N₂ or air with the mono-methoxy complex [Ti(NCMe)Cl(p-tert-butylcalix[4]arene(O)₃(OMe))] performing best.

Synthesis and structures of mono- and di-nuclear aluminium and zinc complexes bearing α-diimine and related ligands, and their use in the ring opening polymerization of cyclic esters

Multi-metallic complexes (of Al, Zn) derived from imine-based ligands effectively operate as catalysts for the ring opening polymerization (ROP) of ε-caprolactone (ε-CL), δ-valerolactone (δ-VL) and co-polymerization thereof.

Topical Administration of Tetrasodium-Mesotetraphenyl-Porphinesulfonate (TPPS) and Red Light Irradiation for the Treatment of Superficial Neoplastic Lesions

In photodynamic therapy, systemic administration of photosensitizing agents induces cutaneous photosensitization in patients. This side-effect can be avoided by topical administration of the agents when only surface lesions are involved. A hydroalcoholic solution of tetrasodium-meso-tetraphenylporphinesulfonate (TPPS) containing Azone, a percutaneous penetration enhancer, was investigated to evaluate its photosensitizing potential in the treatment of 33 primary and recurrent neoplastic lesions of the skin. A complete remission was obtained of lesions with clinical thickness of less than 2 nun. Treatment effectiveness depends on both light and drug penetration through skin. Further studies are in progress to optimize treatment parameters.

A Double Determinant Radioimmunoassay Mov2-Mov8* for Monitoring Ovarian Carcinomas: Definition of the Methodology

A double-determinant radioimmunoassay for the detection of circulating antigens associated with human ovarian carcinoma was developed using two monoclonal antibodies: MOv2 and MOv8 employed respectively as catcher and tracer. The development of the method through three different procedures enabled us to detect the presence of CaMOv2-CaMOv8 carrying molecules in 14 out of 15 ascitic fluids from ovarian carcinoma patients whose tumors were found to be positive with MOv2 and MOv8 monoclonal antibodies by immunofluorescence. Moreover, 13 out of 15 ovarian carcinoma patients presented high levels of antigen in their serum (60-170 Ua/ml). Low levels of antigen were observed in the normal population, the values ranging from 30-40 Ua/ml. However, in 13 out of 100 apparently healthy women high levels of antigen were found in the serum

Homoleptic and heteroleptic bis-NHC Cu(I) complexes as carbene transfer reagents

Homo- and heteroleptic bis-NHC copper(I) complexes have been efficiently used as carbene transfer reagents to Au and Pd. The simple and straightforward procedure allows for the synthesis of well-known gold complexes as well as novel cationic bis-NHC Pd(II) species.

N-heterocyclic carbene copper(I) catalysed N-methylation of amines using CO2

The N-methylation of amines using CO2 and PhSiH3 as source of CH3 was efficiently performed using a N-heterocyclic carbene copper(i) complex. The methodology was found compatible with aromatic and aliphatic primary and secondary amines. Synthetic and computational studies have been carried out to support the proposed reaction mechanism for this transformation.

A general synthetic route to [Cu(X)(NHC)] (NHC = N-heterocyclic carbene, X = Cl, Br, I) complexes

A series of complexes of the type [Cu(X)(NHC)] (X = I, Br, Cl, NHC = N-heterocyclic carbene) was synthesised using a one-pot, mild and user-friendly (aerobic, tech. grade solvents) procedure.

A one-pot procedure for the synthesis of [Cu(X)(NHC)] (X = Cl, Br, I) is reported. The reaction is applicable to a wide range of saturated and unsaturated NHC ligands, is scalable and proceeds under mild conditions using technical grade solvents in air.

Combined physico-chemical treatment of secondary settled municipal wastewater in a multifunctional reactor

In this paper, the physico-chemical treatment of municipal wastewater for the simultaneous removal of pollutant indicators (chemical oxygen demand (COD) and total coliforms) and organic contaminants (total phenols) was investigated and assessed. A secondary settled effluent was subjected to coagulation, disinfection and absorption in a multifunctional reactor by dosing, simultaneously, aluminum polychloride (dose range: 0-150 μL/L), natural zeolites (dose range: 0-150 mg/L), sodium hypochlorite (dose range: 0-7.5 mg/L) and powder activated carbon (dose range: 0-30 mg/L). The treatment process was optimized using computational fluid dynamics (CFD) and response surface methodology. Specifically, a Latin square technique was employed to generate 16 combinations of treating agent types and concentrations which were pilot tested on an 8 m(3)/h multifunctional reactor fed by a secondary effluent with COD and total coliform concentrations ranging from ≈20 to 120 mg/L and from 10(5) to 10(6) CFU/100 mL, respectively. Results were promising, indicating that removal yields up to 71% in COD and 5.4 log in total coliforms were obtained using an optimal combination of aluminum polychloride (dose range ≈ 84-106 μL/L), powder activated carbon ≈ 5 mg/L, natural zeolite (dose range ≈ 34-70 mg/L) and sodium hypochlorite (dose range ≈ 3.4-5.6 mg/L), with all treating agents playing a statistically significant role in determining the overall treatment performance. Remarkably, the combined process was also able to remove ≈ 50% of total phenols, a micropollutant known to be recalcitrant to conventional wastewater treatments.

Photodynamic therapy by topical meso-tetraphenylporphinesulfonate tetrasodium salt administration in superficial basal cell carcinomas

The efficacy of an originally developed photodynamic approach, using topical administration of tetraphenylporphinesulfonate as the photosensitizer, was evaluated in a series of 292 basal cell carcinoma lesions (less than 2-mm thick) in 50 treated patients. The lack of indication for conventional therapies was the main selection criterion. The photosensitizing agent (2% solution) was topically applied at 0.1 ml/cm2, followed by light irradiation with a dye laser emitting at 645 nm (120 or 150 J/cm2). After initial treatment, all lesions responded, with 273 (93.5%) complete responses. Recurrences were observed in 29 (10.6%). A second application of photoradiation was performed in 15 persistent lesions and 11 relapsed lesions, producing 19/26 complete responses. Our results suggest that this technique can be considered a promising alternative treatment modality in selected cases of superficial basal cell carcinomas.

Total resection of glans penis surface by CO2 laser microsurgery

Fifteen patients underwent resection of the whole glans surface with laser microsurgical technique from May 1983 to September 1987. The operations were performed in one stage in 11 cases and in two stages in 4. In 3 cases the resected lesions represented multiple dysplasia grade III or carcinoma in situ, in 1 case hyper/parakeratosis and penile horn, and in 11 cases superficial squamous cell carcinoma. In 8 cases primary superficial and flat tumors occupied more than half the circumference of the organ, and in the remaining 7 cases there were flat, superficial residues after systemic chemotherapy for exophytic, non-infiltrating carcinomas. The CO2 laser beam was used under constant microscopic visual control at a mean output power of 20W, CW or pulsed for the tissue excision from the meatus to the sulcus level. Maximum depth of resection was 2.6 mm. Postoperative external radiotherapy (60 Gy) was given in the first case of the series (microscopically invasive cancer). Satisfactory cosmetic and functional results were observed in all cases. During the follow-up period, ranging from 2 to 48 months, persistent cancer was found at the perimeatal area in 1 case 4 months after laser resection. The procedure can be considered for conservative treatment of wide or multiple superficial lesions of the glans penis.