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Cyclophosphamide (CP) is a cytostatic drug prescribed at large scale, which proved to induce toxic effect on ecosystems and cannot be removed by conventional wastewater treatment processes. Therefore, there is a need to test advanced degradation processes for its removal from wastewater discharges. CP photocatalytic degradation via UV-VIS irradiation was studied using a Nitrogen -doped TiO2 catalyst. The catalyst was synthesized as thin film deposited on glass substrate under nitrogen atmosphere technique. The influence of N2 flow rate and annealing temperature on the CP degradation efficiency was investigated and best photocatalytic activity was obtained for catalyst with 1.8 %wt nitrogen content, synthesized at N2 flow rate=10 sccm, annealed at 550 oC for 1 hour. Its use assure the CP degradation with a pseudo-first order rate constant of 5.262 x 10-4 s-1 and an efficiency of 98 % for an irradiation time of 120. Based on the obtained experimental results in the presence of various scavengers it was found that superoxide radicals are representing the main oxidizing reactive specie involved in CP degradation, but contribution of free hydroxyl radicals from bulk solution is also possible. Degradation intermediates were identified using LC-MS and a possible degradation pathway consisting in three conversion routes was proposed.

In this study, five ultrafiltration membranes (polysulfone, cellulose acetate and polyethe-rsulfone) were tested in the treatment of aqueous protein solutions similar to wastewater from fermentation industries. The experiments were made in tangential flow filtration. The permeate flux for the five membranes tested at the optimum pressure of 3 bar decreased due to the effect of clogging the pores by the macromolecular protein solutions. Cellulose acetate membranes showed the lowest permeate flux (Ac-Cel1=152.4 L/m2.h and Ac-Cel2=40.3 L/m2.h) which doesn�t recommend them for the ultrafiltration process of bovine serum albumin. When a polysulfone membrane was used in several cycles of protein-containing wastewater ultrafiltration, the permeate flow decreased progressively from one cycle to another due to the internal clogging of the membrane (501.6 L/m2.h up to 444.0 L/m2.h). Regarding the ultrafiltration of protein solutions with a suspended yeast content, the clogging was predominant on the membrane�s surface, which results in a decrease of the permeate flux by over 50%.

This study is based to a new concept, to use maize stalk for specific sorption and recovery of Cu(II) and Fe(III) from synthetic solutions. Thus, the sorption properties of the biomass resulting from the recycling of the maize stalk that reached maturity (autumn) were studied. In the first stage, the sorption properties of the maize stalk were evaluated in batch system. Moreover, in terms of water quality improvement several key parameters that influence the sorption equilibrium were evaluated. The effect of contact time (0-120min) and cations initial concentration (investigated range: 0.05-0.4 mg/L) on biomaterial sorption capacity were assessed. Kinetic studies were performed taking into consideration the initial concentration of metallic cation. The experimental data were analyzed based on first order kinetic model, pseudo-second-kinetic model and Morris Webber kinetic model. The kinetics of sorption was in accordance with the pseudo - second - kinetic model as the correlation coefficients showed (R2=0.9940 for Cu(II) and R2=0.9999 for Fe(III)). Moreover the desorption study was evaluated with hydrochloric acid and have detected to be 63% and 89% for Cu(II) and Fe(III) when 4M HCl is used. The surface of the maize stalk loaded with Cu(II) and Fe(III) was characterized by various specific techniques such as FTIR-ATR, SEM, and TG. Experimental results revealed that cations sorption process takes place on the sorbent surface. The sorption rate of each metallic cation is controlled by the formation of chemical bonds with surface polar groups. Their presence on biomass structure, evidenced by FTIR-ATR analysis, explains the behavior of maize stalk as a weak ion exchanger acid.

Ifosfamide (IF) degradation from aqueous system via UV-Vis Fe-TiO2 system was studied for a photo catalyst dose of 200 mg/L and an irradiation time up to 240 min. IF degradation efficiency was monitored via Liquid Chromatography-Mass Spectrometry technique (LC-MS). Experimental photocatalytic tests were performed both in the absence and presence of 2-propanol and F- radicals� scavengers and the results proved that IF degradation occurs most likely in the bulk solution. Experimental results showed that degradation efficiencies for IF varied between 39.52% in the presence of 2-propanol and 70.70% in the scavengers� absence. Six degradation intermediates were identified using the same LC-MS technique and a three stage degradation pathway was proposed based on both available literature data and evolution of degradation intermediates peaks.

Triclosan (TCS) is an antimicrobial agent used for personal care products that cannot be removed by wastewater treatment classical processes. TCS persistence and toxicity is asking for alternative treatment methods such as TiO 2 assisted photocatalyse. Due to the fact that within the literature are presented various pathways for TCS degradation via UV/TiO 2 photocatalysis, some data being contradictory, research work aimed to propose a degradation mechanism supported by as many experimental data. TCS degradation pathways confirmed by experimental results were: addition of hydroxyl radicals at TCS non-phenolic ring, proton extraction by hydroxyl radicals and direct interaction with photo generated electrons.

This paper presents a comparative study on the thermal decomposition in air and FTIR analyses of complex sol-gel precursors used for the deposition of three titania based mesoporous thin films: TiO2, Nb-doped TiO2 and carbon nanotubes (MWCNT)-doped TiO2. The effect of doping with Nb or adding MWCNT on the thermal decomposition of titanium isopropoxide-based precursor and crystallization of TiO2 was investigated through thermogravimetric analysis (TGA), differential thermal analysis (DTA), and Fourier Transform Infrared (FTIR) data. TG-DTA results showed two main exothermic peaks were observed in all samples for the temperature range 280-300 oC and 429-444 oC, corresponding to isopropoxide oxidative decomposition and anatase crystallization. In case of Nb doped TiO2 an oxidative decomposition of Nb ethoxide appears at 198 �C. The acidified MWCNT are thermally stable up to 500�C. Doping TiO2 causes peaks shift to higher temperatures. Also, the effect of heating rate on thermal decomposition for precursors was studied. FTIR analyses were conducted on precursor systems thermally treated at different temperature to track the chemical transformations during the films formation.

New research applications involving the use of cellulosic material derived from maize stalk for on-site treatment of leachate were evaluated for specific removal of Cu(II) and Fe(III) from real, highly polluted tailing pond and mine wastewater samples. Two major issues generated by anthropic mining activities were also tackled: wastewater metal content decrease to improve water quality and subsequently metal specific recovery, increasing the economic efficiency of metal production by using a green technology for residual management. Rapid saturation of the maize stalk mass determined in batch studies and the mine pilot experiment led to diminished metal concentrations in the second pilot experiment, where Cu(II) and Pb(II) from synthetic solutions were monitored in order to test biomaterial performances. In addition, in the second pilot experiment, maize stalk removed Pb(II) in the first 36 h, below the determination limit of the analytical method. The biomaterial bed in the column was saturated after 252 h of inflow solution. FTIR-ATR, TG and SEM techniques probed the interaction between maize stalk polar groups C=O, –OH, C–O and tailing water metallic ions by large FTIR band displacements, intensity decrease and shape changes, modification of thermal stability and by changes in the appearance of adsorbent microstructure images owing mainly to ion exchange mechanism.

International Symposium "The Environment and the Industry", 26-27 September 2019, Bucharest, Romania, pp. 89-90