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Using organic waste and residue streams to be turned into valuable and greener materials for various applications has proven an efficient and suitable strategy. In this work, two green materials (nanosponges and a polymer) were synthesized using potato peels and applied for the first time to adsorb and recover Neodymium (Nd3+) from aqueous solutions. The recovery of Nd3+ that belongs to the rare earth elements has attracted important interest due to its/their importance in several industrial and technological applications. The fine potato peel waste (FPPW) polymer presented an irregular shape and porous surface. At the same time, the β-cyclodextrin (β-CD) nanosponges had uniform distribution with regular and smooth shapes. β-CD nanosponges exhibited a much higher total carboxyl content (4.02 mmol g−1) than FPPW (2.50 mmol g−1), which could impact the Nd3+ adsorption performance because carboxyl groups can interact with cations. The adsorption capacity increased with the increase of the pH, reaching its maximum at pHs 6–7 for β-CD nanosponges and 4–7 for FPPW polymer. The kinetic and equilibrium data were well-fitted by General order and Liu models. β-CD nanosponges attained adsorption capacity near 100 mg Nd per gram of adsorbent. Thermodynamic and statistical physical results corroborated that the adsorption mechanism was due to electrostatic interaction/complexation and that the carboxyl groups were important in the interactions. β-CD nanosponges (three cycles of use) were more effective than FPPW (one cycle of use) in the regeneration. Finally, β-CD nanosponges could be considered an eco-friendly adsorbent to recover Nd3+ from aqueous matrices. [ABSTRACT FROM AUTHOR]

Environmental perception serves as a powerful tool for identifying community needs and potential within their surroundings. This study assessed tourists' environmental perception regarding solid waste and its impact on the Hurtado Balneary, located in Valledupar, Colombia. The investigation delved into the environmental attitudes and behaviors of 769 balneary users by employing a combination of observation, photographic documentation, and a comprehensive 21-question online survey. The findings are 98.8% of participants acknowledged the adverse effects of solid waste on the environment, with 98% demonstrating a willingness to participate in waste management efforts. Furthermore, 42.13% exhibited limited awareness regarding waste management practices, reflecting a concerning lack of public interest and commitment (41.61%). Statistically significant disparities (p > 0.05) emerged 59% of waste items were not appropriately disposed of in designated receptacles. Reasons for this included a lack of a sense of belonging (50.2%) and inadequate environmental education (45.6%). Ninety-six percent expressed the need for river conservation signage, while 59.8% did not undertake any form of environmental training. The study's implications extend beyond the Hurtado Balneary, potentially informing solid waste management strategies in other aquatic environments. This investigation aligns with three Sustainable Development Goals: SDG 12, emphasizing responsible consumption and production; SDG 13, addressing climate action; and SDG 15, advocating for life on land and below water. [ABSTRACT FROM AUTHOR]

The Calophylluminophyllum species annually produces a large volume of cylindrical fruits, which accumulate on the soil because they do not have nutritional value. This study sought to enable the use of this biomass by producing activated biochar with zinc chloride as an activating agent for further application as an adsorbent in batch and fixed bed columns. Different methodologies were used to characterize the precursor and the pyrolyzed material. Morphological changes were observed with the emergence of new spaces. The carbonaceous material had a surface area of 468 m2 g−1, Dp = 2.7 nm, and VT = 3.155 × 10−1 cm3 g−1. Scientific and isothermal studies of the adsorption of the diuron were conducted at the natural pH of the solution and adsorbent dosage of 0.75 g L−1. The kinetic curves showed a good fit to the Avrami fractional order model, with equilibrium reached after 150 min, regardless of the diuron concentration. The Liu heterogeneous surface model well represented the isothermal curves. By raising the temperature, adsorption was encouraged, and at 318 K, the Liu Qmax was reached at 250.1 mg g−1. Based on the Liu equilibrium constant, the nonlinear van't Hoff equation was employed, and the ΔG° were < 0 from 298 to 328 K; the process was exothermic nature (ΔH0 = −46.40 kJ mol−1). Finally, the carbonaceous adsorbent showed good removal performance (63.45%) compared to a mixture containing different herbicides used to control weeds. The stoichiometric column capacity (qeq) was 13.30 and 16.61 mg g−1 for concentrations of 100 and 200 mg L−1, respectively. The length of the mass transfer zone was 5.326 cm (100 mg L−1) and 4.946 cm (200 mg L−1). This makes employing the leftover fruits of the Calophyllum inophyllum species as biomass for creating highly porous adsorbents a very effective and promising option. [ABSTRACT FROM AUTHOR]

Transitioning the productive base to a more sustainable agriculture is one of the great challenges of our time. The current conflicts in Eastern Europe have had a major repercussion on the agricultural commodity market with restricted access and a massive cost increase for some fertilizers used in agriculture. This scenario has led to international concern about food shortages, whereby countries that depend on fertilizer imports need to find mechanisms and new technological paths to reduce their dependence on the international market. The use of crushed rock (soil remineralizers) associated with microorganisms is an important alternative in terms of cost reduction, lower impact on the environment and reduction of external dependence on agricultural inputs. The objective of this work was to evaluate the results of different types of inputs for soil fertilization (crushed rock – remineralizer, organic material and conventional – NPK), the production parameters of quinoa culture (Chenopodium quinoa) and this nutritional content of the crop. The experiment was carried out in a greenhouse and the data were subjected to analysis of variance, the Dunnett's test, complex contrasts, and multivariate analyses. The results showed significant increases in grain filling and quinoa yields, in soil fertility, and in the nutrient content of the aerial parts of plants treated with remineralizers. The treatments containing a mixture of remineralizers and organic compost were superior to those without these inputs, suggesting positive interaction among these sources. This approach may help toward adopting new technologies, especially with the current undersupply of soluble fertilizers. The use of local geological sources (crushed rock) has the capacity to reduce the dependence on imported fertilizers, thus helping to increase agri-food sovereignty in countries and adhering to the principles of agroecology at the local and global levels. [ABSTRACT FROM AUTHOR]

The integrated management of water resources is a requirement for environmental preservation and economic development, with the removal of nutrients being one of the main drawbacks. In this work, the efficiency of a bacterial consortium (Ecobacter WP) made up of eight bacterial strains of the genus Bacillus subtilis, Bacillus licheniformis, Bacillus megaterium, Bacillus cereus, Arthrobacter sp., Acinetobacter paraffineus, Corynebacterium sp., and Streptomyces globisporus was evaluated in the removal of nitrogen compounds in domestic wastewater in a plug flow system, in the extended aeration and bioaugmentation (FLAEBI). To promote the nitrification and denitrification processes, three doses were tested to establish the optimal concentration of the bacterial consortium on a laboratory scale and its subsequent application in an outdoor wastewater treatment plant (WWTP). The evaluation period was 15 days for each treatment in the laboratory and WWTP. The parameters monitored both at laboratory and outdoor were pH, temperature, dissolved oxygen, chemical oxygen demand (COD), biochemical oxygen demand (BOD5), ammonium, nitrites, and nitrates. The results indicated that the optimal concentration of the consortium was 30 mg L−1, with a removal of 92% of nitrate at the laboratory and 62% outdoor. Such a difference is attributed to the different operation residence times and the volume that caused different concentration gradients. The consortium studied can be used to promote nitrification and denitrification processes that intervene in the removal of nitrogenous compounds in plants with similar operating conditions, without investment in restructuring or design modification of the WWTP. [ABSTRACT FROM AUTHOR]

Adequate animal manure disposal became a challenge in agriculture. Liquid swine waste (LSW), easily used in agriculture, presents disadvantages due to the high volume and low nutrient concentrations. Metabasalt powder, a residue of amethyst mining, was evaluated as an adsorbent agent of nutrients (Cu, Zn, P, and K) from LSW. Seven doses of metabasalt powder were tested in proportion with LSW (0, 4, 10, 20, 40, 80, and 160 kg m−3), and during four contact times (CT) (9, 21, 42, and 84 days) and ions were dosed in the liquid and solid fractions. Copper and phosphorus concentrations in the liquid fraction were lower at 21 days of contact. The lowest concentration of zinc in the liquid fraction was observed at the dose of 10 kg m−3 of metabasalt powder, and at 9 days of CT. The K concentrations in the liquid fraction diminished linearly with the metabasalt doses, in which the major dose presented 51% of K compared to the control. The application of metabasalt as an adsorbent agent reduced the contaminant charge in the liquid fraction of LSW, suggesting safe water disposal while promoting ion accumulation in the solid fraction. The use of metabasalt powder became a useful strategy to make LSW pre-treatment on-farm. [ABSTRACT FROM AUTHOR]

By-products from the dairy industry and mining activities represent a great environmental overload, which justify research for value-added reuse of these by-products (dairy sludge and dacite rock powder). Dairy sludge is generated at a rate of about 0.2–10 l per liter of processed milk, and dacite powder, from rock mining extraction and processing, is generated for about 52,400 m3 per year in Nova Prata city, Southern Brazil. For both by-products, the compositions of calcium (Ca), magnesium (Mg), potassium (K) and phosphorous (P), arsenic (As), cadmium (Cd), chromium (Cr), mercury (Hg), and lead (Pb) were determined by using appropriate analytical techniques. A greenhouse experiment was conducted to determine release of macronutrients, such as Ca, K, Mg, and P, from by-products to support black oat (Avena strigosa) and maize nutrition. Twelve by-products doses were blended with a typic Hapludox soil and were applied to pots with five replications each. Black oat (first cultivation) and, sequentially, maize (second cultivation) were cultivated for 70 days each. Ameliorations in soil chemical attributes, leaf dry matter yield, and plant nutritional status were evaluated at the end of each cultivation. There was a significant (p < 0.05) increase in all parameters evaluated in a dose of 7251 kg ha−1 of dacite rock powder and 20,594 kg ha−1 of dairy sludge. Compared to the control treatments, both crops grew well better on all mixtures. The presence of potentially toxic elements in both by-products was irrelevant, indicating that effective blending of dacite rock powder along with dairy sludge could be a potential source of Ca, K, Mg, and P in agriculture without posing a risk of contamination to the environment. [ABSTRACT FROM AUTHOR]

This study was focused on physical, petrographical, mineralogical, and chemical characterization of a volcanic-rock mining by-product (dacite rock), as well as on greenhouse experiment with black oats and maize crops to evaluate the potential use of the by-product as soil re-mineralizer. The by-product sample was obtained from a quarry in the Nova Prata mining district in southern Brazil. The particle size distribution of the by-product and soil was determined by sieving. Dacite rock petrographic description was performed on a polished thin section by optical microscopy. The soil and dacite rock mineralogical phases were identified by X-ray diffraction. The by-product and soil chemical composition was determined by X-ray fluorescence. Inductively coupled plasma mass spectrometry was performed to determine potentially toxic elements, As, Cd, Hg and Pb in by-product. Additional chemical compositions of the by-product and soil were analyzed using a scanning electron microscope equipped with an energy dispersive X-ray detector. Black oats and, sequentially maize, crops were cultivated in a typical Hapludox soil treated with the by-product in a greenhouse. Five by-product doses (0, 906, 1813, 3625, and 7251 kg ha−1) were added into pots containing soil, each with seven replications. Responses to treatments were evaluated from dry matter production, nutritional status of the crops, and in the changes in soil properties after 70 days of each cultivation. The results showed that the by-product is composed of plagioclase, K-feldspar, quartz, clinopyroxene, smectites, and opaque minerals with apatite as accessory mineral. The addition of 3625 and 7251 kg ha−1 doses of the by-product substantially increased the dry matter yield in maize leaves. The Ca uptake by maize leaves cultivated in soil with 7251 kg ha−1 dose of the by-product was significantly higher in soil with other doses, and all by-product doses promoted high concentrations of Mg and Ca. The accumulated amounts of Ca, K, Mg and P indicated that they were enough to supply maize nutritional needs. Improvements in soil properties, such as high levels of Ca, K and P and low levels of exchangeable Al and Al saturation were observed. The results of the study suggest that the by-product can be used as soil re-mineralizer. The dacite rock by-product studied here has potential to be an environmental solution to soil fertilization problem because it does not require chemical processing and can be used as it is mined. [ABSTRACT FROM AUTHOR]