LUCIAN PĂUNESCU, Daily Sourcing & Research SRL,
Bucharest, Romania,
lucianpaunescu16@gmail.com ENIKÖ VOLCEANOV, Faculty of Engineering in Foreign
Language, National University of Science and Technology “Politehnica”
Bucharest, Romania; Metallurgical Research Institute SA Bucharest, Romania
BOGDAN VALENTIN PĂUNESCU, Consitrans SA Bucharest,
Romania
Abstract Replacing the usual alkaline solution with sodium
metasilicate nonahydrate as an alkaline activator of alumina-silicate waste
for the manufacture of geopolymers represents a recent technical solution
for significantly increasing their mechanical resistance. The principle of
this method was tested in an own version by the authors’ team of the current
work. Coal fly ash, river sand, and silica fume (nano-silica) were solid
precursors used in the starting material mixture. Under the conditions of
pressing the geopolymer powder (made by the conventional method) at the
axial pressure of 400 daN·cm-2, compared to its value of 1000 daN·cm-2 used
by (Nishikawa et al., 2022), the level of resistance to compression and
flexure reached values very high, superior compared to that of usual
geopolymers. Keywords: geopolymer composite, alumina-silicate, sodium
metasilicate nonahydrate, pressure, mechanical resistance
BIANCA-MARIA HĂISAN, “Gheorghe Asachi” Technical
University of Iaşi, “Cristofor Simionescu” Faculty of Chemical Engineering
and Environmental Protection, Iaşi, Romania LOREDANA MUNTEANU, “Gheorghe
Asachi” Technical University of Iaşi, “Cristofor Simionescu” Faculty of
Chemical Engineering and Environmental Protection, Iaşi, Romania DUMITRU BULGARIU,
“Alexandru Ioan Cuza” University of Iaşi, Faculty of Geography and Geology,
Iaşi, Romania; Romanian Academy, Filial of Iaşi, Branch of Geography, Iaşi,
Romania RAMONA-ELENA TĂTARU-FĂRMUŞ, “Gheorghe Asachi”
Technical University of Iaşi, “Cristofor Simionescu” Faculty of Chemical
Engineering and Environmental Protection, Iaşi, Romania LAURA
BULGARIU,
“Gheorghe Asachi” Technical University of Iaşi, “Cristofor Simionescu”
Faculty of Chemical Engineering and Environmental Protection, Iaşi, Romania,
laura.bulgariu@academic.tuiasi.ro
Abstract In this study, the effect that inorganic salts have on the
solubilization of phosphorus from chemical fertilizers was analyzed. A
commercial fertilizer (NKP = 15% - 15% - 15%) and the inorganic salts CuSO4,
CaCO3 and CuCl2 were used for the experimental studies. All analyzed samples
were obtained by mechanical mixing a constant amount of solid fertilizer
with 1 – 2% inorganic salts, followed by their dissolution in distilled
water. The obtained results showed that the presence of inorganic salts
significantly affects the solubilization of phosphorus, the decrease in the
concentration of soluble phosphorus in the obtained solutions being 14.5 –
29.6% lower than in the control sample. An important decrease in the
concentration of easily soluble phosphorus can be also observed when
fertilizer samples were place in the soil. The presence of inorganic salts
leads to a decrease in the concentration of soluble phosphorus in the soil
samples by up to 54% compared to the control sample. These results highlight
the effect that inorganic salts have on the efficiency of the use of
phosphorus chemical fertilizers to increase soil quality. Keywords:
chemical fertilizer, phosphorus solubilization, inorganic salts, soil
quality
BOGDAN-MARIAN TOFĂNICĂ, “Gheorghe Asachi” Technical
University of Iași, Iași, Romania ELENA UNGUREANU, “Ion Ionescu de la Brad”
Iași University of Life Sciences, Iași, Romania,
elena.ungureanu@iuls.ro OVIDIU C. UNGUREANU,
“Vasile Goldis” West University of Arad, Arad, Romania MARIA E.
FORTUNĂ,
“Petru Poni” Institute of Macromolecular Chemistry, Iași, Romania IRINA VOLF,
“Gheorghe Asachi” Technical University of Iași, Iași, Romania
VALENTIN I. POPA, “Gheorghe Asachi” Technical University of Iași,
Iași, Romania
Abstract Agricultural residues, traditionally regarded as waste,
represent an abundant and renewable resource that can significantly
contribute to a circular economy. By converting crop byproducts like stalks,
husks, and straw into valuable bioproducts, industries can reduce reliance
on non-renewable resources while minimizing environmental impact. This
article explores the potential of agricultural residues, in various
applications, including biochemicals, biofuels, bioplastics, packaging
materials, biocides, bisorbents and biocomposites. Integrating these
residues into production cycles not only reduces waste and conserves natural
resources but also provides economic benefits to rural communities and
supports sustainable development. Despite challenges like processing costs
and logistical issues, advances in technology and supportive policies are
accelerating the adoption of agricultural residues in circular economy
models to create a closed-loop system where resources are reused, recycled,
and repurposed, minimizing waste and conserving natural resources. This
shift towards repurposing agricultural waste is essential for building a
resilient, low-carbon economy and promoting sustainable resource management. Keywords: Agricultural residues, Circular economy, Lignocellulosic,
Bioproducts, Resource efficiency
CRINUȚA LARISA ORTOVAN, “Gheorghe Asachi” Technical
University of Iaşi, “Cristofor Simionescu” Faculty of Chemical Engineering
and Environmental Protection, Iaşi, Romania CARMEN ZAHARIA, “Gheorghe
Asachi” Technical University of Iaşi, “Cristofor Simionescu” Faculty of
Chemical Engineering and Environmental Protection, Iaşi, Romania,
carmen.zaharia@academic.tuiasi.ro
Abstract This study discusses the experimental results (i.e.
discoloration efficiency and Remazol Rosso RB dye removal) performed in
application of a biosorption step for treatment of a simulated textile
colored wastewater (WW) using dried non-living freshwater green algae-based
materials (Spirogyra algae, size < 2 mm) as biosorbent in free form (S1) and
after heating at 100°C for 6h (S2). Different influencing factors, i.e. pH,
biosorbent dosage, dye concentration, temperature, biosorption time, were
studied for finding the best operating conditions for highest discoloration
and dye removal degrees. The results indicate that the dried green
algal-based material is efficient as biosorbent (i.e. removals of dye and
color in range of 64-91% by S1 biosorbent, and 54-85% by S2 biosorbent; mean
biosorption capacity of 3.325 - 5.435 mg/g) and may be used in the textile
WW treatment for decreasing the organic load and discoloration, especially
in the case of frequent WW flowrate and chemical composition variation, when
is working in the adequate operating conditions. Keywords: biosorption
efficiency, dried non-living green Spirogyra algae, influencing factors,
process variables, Remazol Rosso RB dye, simulated textile wastewater
LUCIAN PĂUNESCU, Daily Sourcing & Research SRL,
Bucharest, Romania,
lucianpaunescu16@gmail.com SORIN MIRCEA AXINTE, Daily Sourcing & Research SRL,
Bucharest, Romania; National Faculty of Applied Chemistry and Materials
Science, University of Science and Technology “Politehnica” Bucharest,
Romania LILIANA MARINESCU, Faculty of Applied Chemistry and Materials Science,
National University of Science and Technology “Politehnica” Bucharest,
Romania
Abstract In this paper, the care for environmental health was
promoted, selecting raw materials that meet these requirements. Thus,
recycled glass waste in predominant proportion, coal fly ash as a by-product
of the energy industry, and a natural alumina-silicate material (metakaolin)
were used. Silicon carbide (SiC) was chosen as an expanding agent. Although
insignificantly used until now for high-temperature industrial processes,
the microwave heating has been adopted to perform the sintering and
expanding process. The results showed very good thermal insulation
properties and high mechanical strength of the optimal expanded product.
Keywords: glass-ceramic, cellular, glass, metakaolin, coal fly ash
ADINA MARIA BAROI (DANILA-DEDIU), “Gheorghe Asachi”
Technical University of Iaşi, “Cristofor Simionescu” Faculty of Chemical
Engineering and Environmental Protection, Iaşi, Romania MARCEL
POPA,
“Gheorghe Asachi” Technical University of Iaşi, “Cristofor Simionescu”
Faculty of Chemical Engineering and Environmental Protection, Iaşi, Romania;
Academy of Romanian Scientists, Bucharest, Romania,
marpopa2001@yahoo.fr LEONARD IONUT ATANASE,
“Gheorghe Asachi” Technical University of Iaşi, “Cristofor Simionescu”
Faculty of Chemical Engineering and Environmental Protection, Iaşi, Romania;
Academy of Romanian Scientists, Bucharest, Romania; Faculty of Medicine,
Apollonia University of Iași, Romania
Abstract The unique environment specific to the oral cavity is
suitable for the proliferation of pathogenic bacteria and infections. The
effectiveness of drug treatment is often reduced due to the fact that saliva
dilutes the mediating formulation and reduces the interaction between the
drug and its site of action. An efficient way to solve this problem is the
creation of polymeric systems sensitive to the action of stimuli that
command the release of the drug at the right place, time and in suitable
doses. Due to their ability to respond to stimuli, hydrogels have been
applied as an excellent drug-delivery system for treatments that include
caries, endodontic diseases, periodontal diseases, bone diseases, mucosal
diseases, oral cancer. The present paper proposes a review of recent
research in the field of obtaining hydrogels that respond to physical
(temperature, UV and visible light) chemical (pH, glucose) and biological
stimuli (enzymes) - smart hydrogels -, with applications in the treatment of
oral cavity diseases. Keywords: hydrogels, oral cavity diseases, drug
delivery system, stimuli sensitive systems, topical administration
CLAUDIU-IONEL CHICUȘ, “Gheorghe Asachi” Technical
University of Iași, Faculty of Civil Engineering and Building Services,
Iași, Romania,
claudiu-ionel.chicus@student.tuiasi.ro GHEORGHE GUGIUMAN,
“Gheorghe Asachi” Technical University of Iași, Faculty of Civil Engineering
and Building Services, Iași, Romania SILVIU CRISTIAN IRICIUC,
“Gheorghe Asachi” Technical University of Iași, Faculty of Civil Engineering
and Building Services, Iași, Romania GELU-RĂZVAN GIMIGA,
“Gheorghe Asachi” Technical University of Iași, Faculty of Civil Engineering
and Building Services, Iași, Romania
Abstract The article analyzes the issue of plastic waste, with a
particular focus on PET (polyethylene terephthalate), both at the national
and global levels, highlighting their environmental impact and the recycling
strategies employed to reduce their negative effects. Recipients made of
polyethylene terephthalate are among the most widely used plastic materials,
especially in the beverage and food packaging industries, and their
accumulation in the environment is a major concern due to their high
resistance to decomposition. The use of plastic waste, particularly PET
(polyethylene terephthalate) bottles, in asphalt mixtures is an innovative
solution that is gaining increasing attention both nationally and
internationally, in the context of reducing the amount of plastic that ends
up in the environment and improving the performance of road infrastructure.
PET is one of the most common types of plastic used in packaging, and
recycling it presents a significant challenge. In this regard, integrating
PET bottles into asphalt mixtures can contribute to reducing plastic waste
and improving the durability of road infrastructure. Keywords:
pollution, plastic waste, recycling, roads, sustainable