Flexible and self-standing membrane composed of ultrafine alumina-silica nanofibers (NFs) has been successfully fabricated by the electrospinning method, and further used as an adsorbent for the adsorptive decolorization of Reactive Red-120 (RR-120) dye from an aqueous system. Effects of pH, adsorbent dosage, and contact time on adsorption have been studied. The adsorption of RR-120 on the NFs was found to be highly pH dependent and the optimum pH was found to be 3. The adsorption equilibrium data was explained well with the Langmuir isotherm model, and the maximum sorption capacity was found to be 884.95 mg/g, which was several folds higher than the adsorption capacity of a number of recently studied potential adsorbents. After adsorption, the NF mat could be separated from the liquid phase conveniently and reused. The sorption kinetics was found to follow an intraparticle diffusion model. The high adsorption performance, excellent flexibility, easy recovery, and reuse characteristic of the alumina-silica NF membrane all favor its practical application in environmental remediation.

Pipe section reactor (PSR) is a well-controlled laboratory reactor, which is used to simulate the water quality variations in drinking water distribution systems. However, the hydraulics condition within PSR, which is an essential prerequisite of the water quality studies, still remains unclear. Consequently, the objective of this study is to analyze the hydraulic conditions within PSR by means of a computational fluid dynamics (CFD) approach. The influences of configuration parameters on the hydraulic conditions were tested including propeller diameter, inclined angle of the propeller, distance between the top and inner cylinder, distance between the bottom and inner cylinder, outer cylinder length, baffle length, number of the baffles, rotational speed of the propeller, and inner and outer cylinder diameters. According to the CFD analysis, an optimal structure of PSR was suggested. The data presented here could facilitate the PSR application and improve the simulation of water quality in distribution systems.

Uranium-contaminated environments pose a risk to human health by means of its transfer to the food chain. Overcoming this issue requires using effective methods to minimize the availability of uranium and other metals in soils. Jordan has a promising project for electricity generation from nuclear power. To move forward with this nuclear project, the Jordan Central Area has been mined for uranium. The expansion of the mining activities in this area led to elevated contents of heavy metal in the surface soil. Phytoremediation efficiency in reducing uranium content from uranium-rich carbonate soil was tested using sunflower plants. Forty-eight sunflower plants were planted in three soil samples containing three different uranium concentrations. The plants were harvested after different planting periods in order to investigate the phytoremediation efficiency over time. The ability of sunflowers to translocate uranium was investigated and the results showed that the translocated amount of uranium to plant increased as the initial concentration of uranium in the soil increased. However, most of the uranium taken up by the sunflower was accumulated in the roots, and only 3% of the uranium concentration in the roots passed to the harvestable shoots. Moreover, the biomass of the plants was not affected by increasing uranium concentration in the plants indicating that sunflower is resistant to radiation and toxicity of uranium at these levels found in the soil.

As a newly emerging persistent environmental contaminant, perchlorate (ClO₄⁻) has adverse effects on thyroid function by inhibiting iodide uptake and could result in neurodevelopment deficits. Our study was performed to investigate the concentration of perchlorate in size-segregated airborne particulate matter (APM) and evaluate its human exposure for children and adults. In this study, 45 size-segregated APM samples were collected from Changsha, China, during July 20 to July 31, 2016. The total APM concentrations ranged from 93.367 to 253.271 μg/m³ (mean 154.651 ± 59.175 μg/m³), and a bimodal size distribution was observed during the sampling period. The concentrations of perchlorate in size-segregated APM were in the range of 0.05–4.99 ng/m³ (mean 2.03 ng/m³). Exposure evaluation indicated that the ingestion was the predominant exposure pathway for daily intake of perchlorate via size-segregated APM, and children are more likely to intake more perchlorate via APM than adults. We suggested that the risk of exposure to perchlorate for children is worthy of attention, and a further study is required, especially for seasonal variations.

It is now acknowledged that aromatic hydrocarbons present in contaminated soils occur in mixtures. The effect of single, binary and quinary mixtures of phenanthrene and selected nitrogen-containing polycyclic aromatic hydrocarbons (N-PAHs) were investigated on the survival, growth and behavioural index of earthworms (Eisenia fetida) over a 21-day incubation in soil. The results showed that the LC₅₀ values ranged from (not detected) ND–329.3 mg kg⁻¹ (single mixture), ND–219.8 mg kg⁻¹ (binary mixtures) to 148.4 mg kg⁻¹ (quinary mixture), while the EC₅₀ values (based on weight loss) ranged from 13.3–148.4 mg kg⁻¹ (single mixture), 63.8–148.4 mg kg⁻¹ (binary mixture) to 24.2 mg kg⁻¹ (quinary mixture). Greater impacts were recorded where N-PAHs are present with phenanthrene. Further, behavioural index of E. fetida was affected after 24-h exposure to N-PAH-amended soils. Among the N-PAHs however, benzo[h]quinoline recorded the greatest impact on the survival, growth and behavioural index of E. fetida in soil. Findings from this study showed that three ring-N-PAHs are more toxic than phenanthrene as expected from their physico-chemical properties. The binary and quinary mixtures of phenanthrene and N-PAHs in soil intensified toxicity, suggesting that PAHs-N-PAHs mixtures represent greater risk to soil biota.

Petroleum products which are used in a wide variety of industries as energy sources and raw materials have become a major concern in pollution of terrestrial and marine environments. The purpose of this study was to assess the potential of indigenous microbial isolates for degradation of diesel fuel. Two most proficient bacterial strains among five isolated strains from polluted soil of an industrial refinery were studied. The isolates then were identified as Pseudomonas aeruginosa and Bacillus subtilis using biochemical tests and 16S rRNA gene sequence analyses. P. aeruginosa showed higher biodegradation efficiency than B. subtilis in shaking flask containing diesel-contaminated water. P. aeruginosa and B. subtilis degraded about 87 and 75% of total hydrocarbons, respectively, in flasks containing 2% diesel and 98% water. The biodegradation efficiency of the isolates decreased as diesel contamination increased from 2 to 5%. The isolates showed significantly higher efficiency on degradation of short-chain hydrocarbons in 20 days, i.e., by using P. aeruginosa, removal efficiency of C₁₀ hydrocarbons was near 90%, while about 69% of C₂₀₊ hydrocarbons and 47% of aromatic hydrocarbons were removed. Therefore, the isolates showed high capability in biodegradation of diesel contamination of the refinery.

The sorption of three organic contaminants with different structure and polarity including non-polar phenanthrene (PHEN), 1,2,4,5-tetrachlorobenzene (TeCB), and polar 1,2-dichlorobenzene (DCB) onto original kaolinite, smectite, vermiculite, and fulvic acid (FA)/humic acid (HA)–clay complexes were investigated, and possible sorption mechanisms were inferred from sorption isotherms and characteristics of humic substances (HS) and HS–mineral complexes. Results showed smectite and vermiculite had stronger sorption ability than kaolinite, and the adsorbed amount of DCB was much higher than that of PHEN and TeCB on each clay. Due to FA/HA-facilitated hydrophobic interaction, FA/HA–clay complexes except FA–vermiculite complex showed a stronger affinity for PHEN and TeCB than the original clays, particularly for HA–clay complexes. The non-linearity parameter values of n for all the Freundlich sorption isotherms of DCB were greater than 1, indicating that clays possessed some unique sites with strong affinity and capacity to sorb DCB from aqueous solutions. FA/HA did not significantly affect the sorption of polar DCB on clays, implying sorption of DCB on clays was probably due to polar interactions between the polar group of DCB and clays. Cation-π bonding between PHEN and iron cation was directly evidenced by X-ray photoelectron spectroscopy, and FA impeded the sorption of PHEN on vermiculite by occupation of iron cation sites. This study will benefit understanding behaviors of contaminants in the soil environments.

The removal of Cu(II), Zn(II), Mn(II), and Fe(II)/Fe(III) from acid mine drainage by using coal bottom ash was investigated at pH 4.2. Metal ion sorption, measured as amount of metal ion sorbed per gram of coal bottom ash (mg/g), was strongly influenced by the L/S (liquid-to-solid ratio), contact time, and equilibrium metal ion concentration. Metal ion sorption increased with increasing contact time as well as the equilibrium metal ion concentration and eventually reached a steady value. Sorption of a particular metal ion from a multi-component solution onto coal bottom ash was always lower as compared to sorption from the single-component solution due to the effect of competing ions. Batch sorption of metal ions onto coal bottom ash followed pseudo-second-order kinetics, while the sorption isotherm followed the Langmuir isotherm model. Removal of metal ions from single- and multi-component metal ion solutions by coal bottom ash followed the sequence: Fe(II)/Fe(III) > Cu(II) > Mn(II) > Zn(II).

Bagasse activated carbon (AC) and the new type of activated carbon (KAC) prepared with reactivation method of ZnCl₂-KOH were modified with triethylenetetramine (TETA) and tetraethylenepentamine (TEPA). The as-modified adsorbents for CO₂ separation were investigated by thermal gravimetric analysis (TGA), Fourier transform infrared spectroscopy (FTIR), elemental analysis, N₂ adsorption–desorption, as well as scanning electron microscopy (SEM). When the content of amine group is 5%, the CO₂ adsorption quantity of TEPA-loaded adsorbents reaches the highest at 60 °C (3.62 mmol/g for KAC and 1.98 mmol/g for AC, respectively). With a more abundant pore structure, KAC is more suitable for amine modification and its adsorption capacity of CO₂ is higher than that of AC after amine modification. Cyclic adsorption–desorption tests showed satisfactory regenerations for the modified adsorbents. Compared with other adsorbents, such as activated carbon, microporous zeolite, and mesoporous molecular sieve reported in literature, the new adsorbent prepared from the by-product of sugar industry has good performance (1.05–3.14 mmol/g larger than those of others) under the same conditions (60 °C and 15% partial pressure). The results are expected to provide scientific basis for the practical application.

While governments and individuals strive to maintain the availability of high-quality water resources, many factors can “change the landscape” of water availability and quality, including drought, climate change, saltwater intrusion, aquifer depletion, population increases, and policy changes. Specialty crop producers, including nursery and greenhouse container operations, rely heavily on available high-quality water from surface and groundwater sources for crop production. Ideally, these growers should focus on increasing water application efficiency through proper construction and maintenance of irrigation systems, and timing of irrigation to minimize water and sediment runoff, which serve as the transport mechanism for agrichemical inputs and pathogens. Rainfall and irrigation runoff from specialty crop operations can contribute to impairment of groundwater and surface water resources both on-farm and into the surrounding environment. This review focuses on multiple facets of water use, reuse, and runoff in nursery and greenhouse production including current and future regulations, typical water contaminants in production runoff and available remediation technologies, and minimizing water loss and runoff (both on-site and off-site). Water filtration and treatment for the removal of sediment, pathogens, and agrichemicals are discussed, highlighting not only existing understanding but also knowledge gaps. Container-grown crop producers can either adopt research-based best management practices proactively to minimize the economic and environmental risk of limited access to high-quality water, be required to change by external factors such as regulations and fines, or adapt production practices over time as a result of changing climate conditions.