Adsorption simulation of 2,4-D pesticide on novel zinc-based 2-amino-4-(1H-1,2,4-triazole-4-yl)benzoic acid coordination complexes using machine learning approach.

The capacity of zinc-based 2-amino-4-(1H-1,2,4-triazole-4-yl)benzoic acid coordination complex (Zn(NH2-TBA)2) and modified Zn(NH-TBA)2COMe complex for removal of 2,4-dichlorophenoxyacetic acid (2,4-D) from aqueous solutions was investigated through adsorption modeling and artificial intelligence tools. Analyzing the adsorption characteristics of pesticides helps in studying the groundwater pollution by pesticides in agriculture area.In this study, Zn(NH2-TBA)2 was synthesized using Schiff base and its surface was modified using acetic anhydride group and their physical characteristics were identified using proton NMR, FTIR, and XRD. NMR results showed maximum modification yield obtained was 65% after 5 days. The porous structure and surface area monitored using nitrogen isotherm and BET surface area analysis presented relatively less surface area and porosity after modification. Adsorption modelling indicated that Toth model with a maximum adsorption capacity of 150.8 mg/g and 100.7 mg/g represents the homogenous adsorption systems which satisfy both low- and high-end boundary of adsorbate concentration in all settings according to the optimum point, while the kinetics and rate of 2,4-D adsorption follow the pseudo-first-order kinetic model in all situations. Artificial neural network (ANN), support vector regression, and particle swarm optimized least squares-support vector regression (PSO-LSSVR) were used for the optimization and modelling of adsorbent mass, adsorbate concentration, contact time, and temperature to develop predictive equations for the simulation of the adsorption efficiency of 2,4-D pesticide. The obtained results exhibited the better performance of ANN and PSO-LSSVR for prediction of adsorption results. The mean square error values of ANN (0.001, 0.012) and PSO-LSSVR (0.121, 0.105) were obtained for Zn(NH2-TBA)2 and Zn(NH-TBA)2COMe, respectively, while their respective coefficient of determination (R2) obtained were 0.999 and 0.988 for ANN and 0.980 and 0.825 for PSO-LSSVR. The study specified that machine learning predictive behavior performed better for Zn(NH2-TBA)2 compared to Zn(NH-TBA)2COMe that is also supported by theoretical kinetics and isotherm models. The research concludes that artificial intelligence models are the most efficient tools for studying the predictive behavior of adsorption data.

Photodegradation of Rhodamine B using gallium hybrids as an efficient photocatalyst.

Keeping in view the toxicity of the Rhodamine B, the present study is designed to remediate the water loaded with toxic dyes using gallium oxide and gallium hybrids as photocatalyst. Precipitation coupled with sonochemical method is adopted for the synthesis of gallium oxide while the post grafting method is adopted for the synthesis of gallium hybrids with the indole and its derivatives. FTIR spectra showed the characteristic absorption bands of gallium oxide and gallium hybrids at 400-700 cm-1 and 1400-1600 cm-1. SEM and XRD showed the micro-sized rectangular rod-shaped gallium oxide with rhombohedral geometry. The average crystallite size of gallium hybrids was 26-32 nm calculated using the Debye Scherrer and Williamson-Hal models. The BET isotherm of gallium hybrids revealed the adsorption type-IV and hysteresis loop (H3) proposing multilayer and mesoporous structures with increase in surface area from 26 m2/g of gallium oxide to 31 m2/g of gallium-indole, 35 m2/g of gallium-methyl indole, and 37 m2/g of gallium-carboxylic indole. XPS showed the presence of gallium (3-14%), oxygen (28-32%), nitrogen (23-46%), and carbon (9-46%). The gallium oxide and gallium hybrids showed 47-72% optimum degradation of Rhodamine B under 2 h of illumination at pH 7 and 0.03 mg/L. The degradation rate followed a Langmuir-Hinshelwood model with R2 > 0.9.

Synthesis & fabrication of O-linked polymeric hybrids for recovery of textile dyes: Closed loop economy.

Dyes are an important resource employed for the production systems in textile, paper, paint and leather industry. An estimate of 200,000 tons of dyes are discharged as textile effluent each year worldwide. It becomes imperative to recover these dyes by treating the effluents using economically viable routes. The present research was undertaken with the objective to attain zero emission and zero waste through development of novel polymeric hybrids as adsorbents. For this purpose, metal moieties (Al3+, Si4+, Ti4+ and Zr4+) were hybridized with polyacrylic acid, and cellulose acetate for the uptake of selected dyes under optimized parameters. The structural elucidation of four synthesized hybrids (MP-Al, MP-Si, MP-Ti and MP-Zr) by FTIR, EDX and TGA confirmed O-linked grafting of metal moieties with polymers and thermally stable porous materials. SEM micrographic images displayed void spaces providing channels for effective adsorption. The batch experiments demonstrated removal of malachite green (77-96%) and congo red (70-82%) upon contact of initial 45 min on polymeric hybrids On the other hand, pristine polyacrylic acid and cellulose acetate showed remarkably low removal of dyes. The adsorption mechanism is proposed as physical in nature following type II isotherm. Further, Langmuir and Ho's pseudo second order fitness was evaluated. In order to determine the economic viability of the present research, the real textile dyes were recovered in three consecutive cycles of adsorption and chemical treatment of hybrids. The results propose a system with positive impact on economy by maximum utilization of hybrids as adsorbents and recovery of textile dyes for reuse in textile processing.

Fabrication of polysulfone mixed matrix membrane for wastewater treatment.

Recent development in separation technologies has envisioned a green and sustainable future that encouraged energy preservation and waste minimization. The concept of a clean future emphasizes on retrieval and reutilization of valuable products from waste streams to improve the water quality. Membrane-based separations are currently explored as an auspicious substitution over traditional separation processes. The present study is designed to purify water using aluminum and gallium mixed matrix membranes from toxic metals (Lead and Mercury) and dyes (Rhodamine B, and Reactive Blue-4). Facile protocol i.e., immersion precipitation phase inversion method was used for the fabrication of mixed matrix membrane. The aluminium and gallium hybrids act as a filler and create heterogeneity and hydrophilicity within the membrane, affirming better water permeability and mechanical strength. The performance of fabricated mixed matrix membranes is evaluated using a lab-based dead-end membrane filtration unit. The result showed 30-71% rejection of Mercury, 24-65% rejection of Lead, 12-66% rejection of Reactive Blue-4, and 15-80% rejection of Rhodamine B.

Development of Ag0.04ZrO2/rGO heterojunction, as an efficient visible light photocatalyst for degradation of methyl orange.

Methyl orange (MO) is mutagenic, poisonous, and carcinogenic in nature, hence, effective methods are required for its degradation. We have synthesized pure ZrO2, Ag-doped ZrO2, and Ag-doped ZrO2/rGO as hybrid photocatalysts by facile hydrothermal method. These photocatalysts were characterized by powder XRD, scanning electron microscopy, EDX, FTIR, photoluminescence, UV-Vis diffuse reflectance (DRS), and Raman spectroscopy. The photodegradation of MO (10 ppm) was studied with pure ZrO2, Ag-doped ZrO2, and Ag-doped ZrO2/rGO (10 mg/100 mL catalyst dosage) photocatalysts at 100 min irradiation time under UV-Visible light. The pH effect and catalyst dosage on photodegradation of MO was investigated. Ag0.04ZrO2/rGO photocatalyst exhibited the maximum photocatalytic degradation of MO (87%) as compared to Ag0.04ZrO2 (60%) and pure ZrO2 (26%). Reusability experiments ensured the excellent stability of photocatalyst after five consecutive experiments. To the best of our knowledge, this is the first report on the facile hydrothermal synthesis of Ag0.04ZrO2/rGO photocatalyst for photocatalytic degradation of methyl orange.

A Quantitative Assessment and Biomagnification of Mercury and Its Associated Health Risks from Fish Consumption in Freshwater Lakes of Azad Kashmir, Pakistan.

Issues regarding biomagnification of mercury (Hg) due to its persistence, bioaccumulation, and toxicity in freshwater lakes have gained much attention in the last two decades especially in remote regions of the world where anthropogenic inputs are considered as negligible. In this study, spatial distribution of total mercury (THg), interspecific accumulation patterns, trophic transfer, and associated health risks in fish of freshwater lakes (357-3107 masl) in Azad Kashmir, Pakistan, were investigated. THg concentrations in the regions were 0.20 ± 0.08 µg g-1 in glacial, 0.54 ± 0.21 µg g-1 in rural, and 1.35 ± 0.46 µg g-1 in urban region. Omnivorous, herbivorous, and carnivorous fish showed THg concentrations of 0.94, 0.85, and 0.49 µg g-1. Regional, lake, trophic level, and specie-specific differences of THg accumulation were found significant in the study. Among growth parameters, length and age varied significantly among species, trophic levels, and lakes, whereas weight showed significant variation among lakes as well. Condition factor (K) showed significant differences within species, lakes, and trophic levels. Biomagnification was observed in all lakes with the trophic magnification slopes (TMS) ranging from 0.03 to 0.20 with an average of 0.094 ± 0.07. Isotopic values of nitrogen (δ15N) and condition factor were found to dominate THg accumulation trends; however, no significant health risks were found in the study.

Sonochemical synthesis of aluminium and aluminium hybrids for remediation of toxic metals.

Spherical shaped nano-size aluminium oxide and its hybrids with indole and indole derivatives have been synthesized using sol-gel and post grafting methods coupled with sonication (Branson Digital SonifierS-250D; 20 kHz; 40%) for the remediation of toxic metals (lead and mercury). Different spectroscopic techniques (FTIR, SEM, BET, XRD, and XPS) have been applied to assess the properties of synthesized aluminium oxide and its hybrids. FTIR spectra showed the absorption bands of aluminium oxide (Al-O-Al) and aluminium hybrids (Al-O-C) at 800-400 cm-1 and 1650-1100 cm-1 region, respectively. SEM showed spherical shaped clusters of aluminium oxide which changed into the net-shape structure after the hybrid synthesis. It is worth noting that sonication energy increases the total surface area of aluminium oxide when it gets hybridized with indole and its derivatives from 82 m2/g to 167 m2/g; it also improved the product yield from 68% to 78%. Simultaneously, FTIR, SEM and BET analysis of non-sonicated aluminium oxide and its hybrids were also recorded for comparison. While XRD and XPS analysis were only conducted for sonicated aluminium oxide and its hybrids to manifest the structural and compositional properties. XRD patterns indexed as the cubic crystal system with an average 41 nm crystallite size of sonicated aluminium oxide which remains unaffected after hybrid synthesis. A survey scan under XPS confirmed the presence of all expected elements (aluminium, oxygen, carbon, nitrogen) and deconvolution of each recorded peak showed binding of element with its neighboring elements. The performance of aluminium oxide and its hybrids synthesize with and without sonication are also evaluated using a time-dependent batch adsorption protocol optimize for one hour. The maximum adsorption of lead (37%) and mercury (40%) are found onto sonicated aluminium oxide. The sonicated aluminium hybrids showed 43-63% of lead and 55-67% of mercury at pH 7. The fitness of experimental data using adsorption kinetics and isotherms revealed that adsorption follows Pseudo-second-order kinetic, Langmuir, and Freundlich isotherms.

In situ remediation of 2,4-dicholrophenoxyacetic acid herbicide using amine-functionalized imidazole coordination complexes.

Demand of clean water is always a major concern due to continuous use of toxic pesticides and herbicides to overcome food scarcity. In Asian countries, wide use of ionizable 2,4-D herbicide has worsen problem due to its less binding ability with soil and can easily contaminate drinking water that causes potential risks to humans and environment. The present research focused on synthesis of amino-factionalized coordination complexes using imidazole-based amino benzoic acid ligands for remediation of acidic 2,4-D herbicide. Coordination complexes characterized with FTIR, 1H-NMR, elemental analysis, thermogravimetric analysis, powder XRD, and BET revealed successful incorporation of functionalized groups with high thermal stability and surface area that make them suitable for adsorption experiments. Batch adsorption experiments conducted at different temperature conditions depicted the spontaneous physisorption process (- ∆G) having endothermic nature (∆H, ∆S). The removal efficiency of the amino-functionalized coordination complex is found to be higher (73%) compared to non-functionalized (35%) and acetic anhydride-functionalized coordination complex (42%). Kinetic studies supported pseudo 2nd-order kinetics with three phases of adsorption depicted by intra-particle diffusion model. Amino-functionalized complexes favored Langmuir isotherm while Freundlich isotherm is best fitted for non-functionalized complexes. The synthesized adsorbents were also proven to be effective for removal of herbicide from irrigated wastewater with average percent removal of 56% for amino functionalized, acetic anhydride functionalized (23%), and non-functionalized (20%).

Hybrid mesoporous silicates: A distinct aspect to synthesis and application for decontamination of phenols.

Water pollution due to organic compounds is of great concern and efforts are being made to develop efficient adsorbents for remediation of toxic pollutants. The development of new functionalized materials with increased performance is growing to meet the regulatory standards in response to public concerns for environment. In this study, an attempt has been made to investigate the influence of synthesis parameters like the reaction temperature, the surfactant-to-silica ratio and reaction time on the structural and textural properties of novel ordered mesoporous silica hybrids. In order to understand the effect of different synthesis parameters, all the prepared materials were systematically characterized by various analytical, spectroscopic and imaging techniques such as XRD, BET, TG etc. It was deduced from these studies that the synthesis temperature influence greatly the structural order whereas both the P104/Na2SiO3 molar ratio and reaction time found to influence textural properties significantly. However, under optimized experimental condition, we could achieve the functionalized silica hybrids that offers successful incorporation of -Amino, -Glucidoxy, -Methacrylate, -Vinyl and -Phenyl moieties indicated by FTIR peaks at 793 cm-1, 2870 cm-1, 796 cm-1, 1630 cm-1 and 954 cm-1. XRD studies reveal orthorhombic and tetragonal symmetry for the hybrids and these materials were found to be thermally stable due to incorporation of organic moiety in silica matrix. Functionalized silica hybrids then applied as adsorbents demonstrated efficient and comparable removal of 4-aminophenol and p-nitrophenol in 20 min facilitated through organic moiety. Detailed modeling of the sorption using equilibrium and kinetic isotherms has been carried out to get an insight into the transport process. The adsorption isotherms of phenol derivatives are well-fitted with the Langmuir, Freundlich and Temkin Isotherms and the adsorption kinetics follows the pseudo second order model. The modeling confirms that the uptake is a chemisorption process.

Removal of pirimicarb from agricultural waste water using cellulose acetate-modified ionic liquid membrane.

Insecticide spray in fruit gardens is a very common practice in different districts of Pakistan. These toxic sprays not only deteriorate the taste of fruit but also due to wet deposition travel through soil, they reach groundwater via leaching process. In the present study, imidazolium-based ionic liquid ([C2im][C3H6NH2]Br-) and its cellulose acetate-supported membrane ([CA-C2im][C3H6NH2]Br-) was prepared and characterized using FTIR, XRD, and SEM. These materials are used as adsorbents for the removal of "Pirimicarb" (an insecticide from waste water). A closed batch at varying parameters, i.e., concentration and temperature as function of time, was conducted on UV-Vis spectrophotometer. Comparison of removal capacity exposed better (74%) adsorption trend by CA-IL membrane than ionic liquid (68%). Thermodynamic studies projected spontaneous process (-ΔG), favoring endothermic reaction (ΔH, ΔS). Kinetics supported pseudo-second order reaction while fitness of isothermic models (Langmuir, Freundlich, Temkin) proposed multistep intraparticle diffusion process.

Ultrasound-assisted synthesis of gallium hybrids for environmental remediation application.

Micron-sized, rhombohedral shaped gallium hybrids with different indole derivatives (indole, 2-methyl-indole, indole-2-carboxylic acid) were successfully synthesized with precipitation method coupled with ultrasound followed by the post-grafting method. The as-synthesized hybrid materials were characterized using FTIR, SEM, XPS, XRD, and BET techniques. FTIR spectra showed characteristic absorption bands of gallium oxide and gallium hybrids at 400-700 cm-1 and 1400-1600 cm-1. SEM, XRD, and BET showed that ultrasound-assisted gallium micro-particles are porous, crystalline possessing high surface to volume ratio as compared to that synthesized in the absence of ultrasound. Survey scan of XPS revealed the presence of gallium, oxygen, nitrogen, and carbon. The as-synthesized gallium hybrids were applied as a potential photocatalyst towards Reactive Blue 4 (model pollutant) using batch adsorption experiment under visible light. It showed maximum 30-65% degradation within two hours and followed a pseudo-first-order kinetic model with R2 > 0.9.

Application of bioenzymatic soil stabilization in comparison to macadam in the construction of transport infrastructure.

uver ninety percent or roaas anc nignways are pavea witn aspnait as it is less expensive, iexime and easy to construct and repair in comparison to concrete. The increasing effect of climatic change and cost of construction materials have forced to consider environment friendly methods to build roads. One economically feasible solution for achieving these objectives is use of enzyme soil stabilization. Use of bioenzymes is known to improve the stability of aggregates and soil materials in the roadways and other pavement structures. The present study was designed to introduce environment friendly TerraZyme to increase engineering qualities of soil for road construction. Soil classification and earth work characteristics were analyzed for two soil types representing pulverized local and transported soil with and without TerraZyme. Obtained results confirmed that treatment with TerraZyme increased engineering characteristics as indicated by increase in CBR values from 10.47 to 16.28 with 55 % improvement, increase of 4.28 % and 2.20 % in dry density and decrease of 18.13 % and 6.17 % in moisture content for untreated and treated soils, respectively. TerraZyme constructed roads will be effective for cost saving upto 15-20 % and maintenance cost reduction of60 % as compared to normal water bound Macadam road.

Chemodynamics of methyl parathion and ethyl parathion: adsorption models for sustainable agriculture.

The toxicity of organophosphate insecticides for nontarget organism has been the subject of extensive research for sustainable agriculture. Pakistan has banned the use of methyl/ethyl parathions, but they are still illegally used. The present study is an attempt to estimate the residual concentration and to suggest remedial solution of adsorption by different types of soils collected and characterized for physicochemical parameters. Sorption of pesticides in soil or other porous media is an important process regulating pesticide transport and degradation. The percentage removal of methyl parathion and ethyl parathion was determined through UV-Visible spectrophotometer at 276 nm and 277 nm, respectively. The results indicate that agricultural soil as compared to barren soil is more efficient adsorbent for both insecticides, at optimum batch condition of pH 7. The equilibrium between adsorbate and adsorbent was attained in 12 hours. Methyl parathion is removed more efficiently (by seven orders of magnitude) than ethyl parathion. It may be attributed to more available binding sites and less steric hindrance of methyl parathion. Adsorption kinetics indicates that a good correlation exists between distribution coefficient (Kd) and soil organic carbon. A general increase in Kd is noted with increase in induced concentration due to the formation of bound or aged residue.