Phytoremediation of dye contaminated soil by Leucaena leucocephala (subabul) seed and growth assessment of Vigna radiata in the remediated soil

Metabolites produced by inoculated Vigna radiata during bacterial assisted phytoremediation of Pb, Ni and Cr polluted soil

Phytoremediation assisted with plant growth promoting bacteria (PGPB) is a green technology to remediate metal contaminated soils. Plants usually produce secondary metabolites to tolerate metal toxicity. Present study was designed to explore the phytoremediation potential of Vigna radiata var. NM-II in the presence of metal resistant PGPB and comparison of metabolites produced under heavy metal stresses (Pb, Ni, Cr). Three PGPB selected for present study include Bacillus pumilus MB246, Serratia nematodiphila MB307 and Delftia Lacustris MB322. Pot experiments were conducted with inoculated V. radiata NM-II seeds grown in soil artificially contaminated with lead (Pb), Nickle (Ni) and chromium (Cr) at a concentration of 300, 200 and 100 mg/kg respectively. After harvesting various growth parameters were studied (root length, shoot length, fresh weight and dry weight). Bacterial colonization on root surfaces of harvested plants was observed through Scanning electron microscopy (SEM) and Elemental composition was recorded through Energy dispersive X-ray spectroscopy (EDX) attached with SEM. Metabolic response of harvested plants was studied through Gas chromatography Mass spectrophotometry (GC-MS) analysis. Metal accumulation in roots, shoots and soil was analysed by acid digestion method from which Bioaccumulation factor (BF) and Translocation factor (TF) of metal from soil to plant was calculated. Results revealed stimulatory effect of PGPB on growth and phytoextraction ability of V. radiata. Soil metal removal efficiency was in the order Pb>Ni>Cr, whereas metal distribution in each part of plant was root>stem>leaf. The BF and TF values suggested V. radiata as Pb and Ni excluder while moderate accumulator for Cr. Elemental analysis through Energy Dispersive X- ray spectroscopy (EDX) found potassium (K+)and calcium (Ca+)as highly abundant nutrients with least accumulation of sulphur (S). Metabolites study through GC-MS revealed variety of compounds (carbohydrates, amino acids, fatty acids, steroids etc) detected differentially under each metal treatment and their concentration was influenced by different bacterial inoculations. Overall 9-Octadecenamide was found as commonly present lipid compound in most of the treatments which is required for detoxification in plants. The study concluded beneficial role of PGPB for successful phytoremediation of heavy metals and differential response of metabolites towards each metal stress that is related to metal tolerance ability of V. radiata.

Integrated physical-biological treatment system for batik industry wastewater: A review on process selection

Batik is well known as one of the unique identifiers of the Southeast Asian region. Several countries that still preserve the batik heritage are Malaysia, Indonesia, China and India. The Batik industry holds a significant place in Malaysia's craft-based industry. In Malaysia, batik motifs and patterns are mostly hand-drawn and painted directly on fabric, therefore, each one is unique. The players in the Batik industry are mostly small businesses and cottage industries, particularly in the states of Kelantan, Terengganu, Pahang, Sabah and Sarawak. However, their market growth and contribution are not synchronized with the treatment system. The wastewater generated by this industry rarely meets standard effluent requirements and regulations, thus worrying the authorities. Batik wastewater is categorized as one of the highly polluted wastewaters. The toxicity of pollutants from batik may reduce environmental quality and pose a risk to human health. Batik wastewater needs extensive treatment, since no complete and appropriate treatment has been applied for so many years in specific batik industries. This paper reviews the batik industry in Malaysia, its wastewater generation and the available current treatment practices. It discusses integrated treatments of coagulation-flocculation and phytoremediation technology as a batik wastewater treatment process with potential utility in the batik industry. This review may become part of the guidance for the entire batik industry, especially in Malaysia.

Transport Behavior of RB5 Dye in Alluvial Soil in the Northeast of Brazil

The textile industry generates a large volume of chemically diversified effluents containing, among other compounds, dyes. Untreated wastes are contaminants to surface water, soil, and groundwater. In this aspect, various studies have explored the issue of contamination of alluvial soils in the Alto Capibaribe region, northeast of Brazil, due to local textile activity. This region, inserted into the Brazilian semiarid region, suffers from water scarcity, and there is a need for rural communities to use alluvial formations for water supply. The simulation of solute transport is a fundamental tool for understanding the environmental performance and risks associated with contamination by textile dyes. Transport parameters that directly influence pollutant dynamics in sedimentary environments are characterized. This study evaluated the retention and mobility of the dye Remazol Black 5 (RB5) in two superficial layers of alluvial soil from Alto Capibaribe to obtain transport parameters. In the laboratory, tests of mobility in soil columns with RB5 dye (concentration of the 25 mg L−1) and KBr tracer (concentration of the 35.7 g L−1) solutions were conducted. The CDE and two-region models were used to model the KBr experimental transport data, and the two-site model was used to model the RB5 experimental transport data. Physical non-equilibrium was found in the soils for KBr transport, and the two-region model adequately modeled the experimental breakthrough curves (BTCs). For the transport of RB5, the results showed a chemical non-equilibrium, and the two-site model was adequate to model the experimental BTCs. The results indicate that the surface layer is most responsible for the retention of RB5, where the RB5 solution was less mobile than in the lower layer. Both layers showed low retention and high mobility for RB5, indicating that the RB5 dye in the region may contaminate groundwater.

Magnetic nanocomposites for sustainable water purification-a comprehensive review

Numerous contaminants in huge amounts are discharged to the environment from various anthropogenic activities. Waterbodies are one of the major receivers of these contaminants. The contaminated water can pose serious threats to humans and animals, by distrubing the ecosystem. In treating the contaminated water, adsorption processes have attained significant maturity due to lower cost, easy operation and environmental friendliness. The adsorption process uses various adsorbent materials and some of emerging adsorbent materials include carbon- and polymer-based magnetic nanocomposites. These hybrid magnetic nanocomposites have attained extensive applications in water treatment technologies due to their magnetic properties as well as combination of unique characteristics of organic and inorganic elements. Carbon- and polymer-related magnetic nanocomposites are more adapted materials for the removal of various kinds of contaminants from waterbodies. These nanocomposites can be produced via different approaches such as filling, pulse-laser irradiation, ball milling, and electro-spinning. This comprehensive review is compiled by reviewing published work of last the latest recent 3 years. The review article extensively focuses on different approaches for producing various carbon- and polymer-based magnetic nanocomposites, their merits and demerits and applications for sustainable water purification. More specifically, use of carbon- and polymer-based magnetic nanocomposites for removal of heavy metal ions and dyes is discussed in detail, critically analyzed and compared with other technologies. In addition, commercial viability in terms of regeneration of adsorbents is also reviewed. Furthermore, the future challenges and prospects in employing magnetic nanocomposites for contaminant removal from various water sources are presented.

Photocatalytic activity of SnO2/Fe3O4 nanocomposites and the toxicity assessment of Vigna radiata, Artemia salina and Danio rerio in the photodegraded solution

The study was undertaken to design SnO₂/Fe₃O₄ nanocomposite by sonochemical method and to assess the photodegradation of organic dye. Textural, composition and structural features of the bare SnO₂ and SnO₂/Fe₃O₄ samples were characterized using scanning electron microscope (SEM), energy dispersive X-ray (EDX), X-ray diffraction (XRD), and Fourier transform infrared spectroscopy (FTIR). The X-ray diffraction of as-synthesized SnO₂/Fe₃O₄ nanocomposites confirms the presence of tetragonal and cubic structure. The results disclose that the incorporation of Fe₃O₄ in SnO₂ decrease the crystallite size and increase the surface area compared with bare SnO₂ nanoparticle. The as-prepared photocatalyst shows higher efficiency than the bare SnO₂ under sunlight irradiation. Vigna radiata seeds (VR), Artemia salina (AS) and Zebra fish (Danio rerio (DR) were used to check the toxicity level of the treated and untreated Rhodamine B (RhB) dye solution. These models displayed good consistency for examining the harmfulness of the solutions. The results suggests SnO₂/Fe₃O₄ nanocomposite exhibited a good efficacy in the dye wastewater treatment. Further, the degradation efficiency was confirmed by the toxicity examination.

Phytoremediation of polluted soils and waters by native Qatari plants: Future perspectives

Because pollution is predicted to worsen and sources of quality water for agriculture and other human activities are limited, many countries have been motivated to seek novel water sources. Qatar relies on groundwater and water desalinization to meet its water needs, and additional water resources will be needed to avoid unexpected crises in the future. Industrial wastewater (IWW) is an alternative water source, and much research activities should be focused on developing innovative and contemporary approaches to removing pollutants from IWW. Phytoremediation methods, shown to be efficient methods of removing and degrading contaminants of various kinds from polluted waters and soils, require knowledge of the native plants and associated microorganisms. In Qatar, many native plants (monocot and dicot, indigenous or introduced) have been shown to be greatly effective in remediating polluted areas. This article is a guide for Qatari scientists aiming to identify promising native plants and associated microbes for IWW phytoremediation. In it, we review the basic components of bioremediation and summarize the principle phytoremediation approaches and preferred recycling options. The multiple mechanisms and methods of phytoremediation for cleansing polluted soils and waters are also discussed as are details of the metabolic reactions degrading the organic components of oil and gas. Finally, heavy metal accumulation is addressed. Wastewater from industrial and domestic activities is currently being used to create green areas around Doha, Qatar, and such areas could be at risk of contamination. Many native Qatari plants and soil-dwelling microbes are efficient at removing organic and inorganic contaminants from polluted soils and waters, and some are promising candidates for achieving a clean environment free of contaminants.

Bacopa monnieri (L.) Pennell, a potential plant species for degradation of textile azo dyes

The current study highlighted the phytoremediation potential of Bacopa monnieri (L.) Pennell for most commonly used azo dyes which are resistant to degradation. Fourteen azo dyes (reactive: 09; direct: 05) upon treatments up to 40 mg/L were decolorized in the range of 90 to 100% after incubation of 2 weeks in in vitro and hydroponic cultures. No significant alteration in growth of B. monnieri was observed in the presence of dyes R. Magenta MB, R. Navy Blue M2R, Dt. Orange RS, Dt. T Blue GLL, Dt. Sky Blue FF alone, and together in the medium. However, at increasing concentrations (60-100 mg/L), the percent dye decolorization was declined and showed a toxic effect on plant growth. The chlorophyll content declined while membrane damage and osmolyte accumulation were increased in dye treated samples. The biological conversion of produced metabolites was analyzed using FTIR and GC-MS. Our results suggest that the intermediates of Dt. Blue GLL degradation consist L-Proline, N-valeryldecyl ester, 3,5 Di-tert-butyl-4-trimethylsiloxytoulene, and 1,2-benzenedicarboxylic acid, diisooctyl ester. The antioxidative and oxidative enzyme activities in roots and leaves were significantly higher in the presence of dyes over control indicate that these enzymes are involved in degradation of dyes. Percentage seed germination, shoot and root length of seedlings of legume, cereal, and oilseed crop was not affected, suggesting the compatible nature of the produced metabolites. Our results revealed the remarkable ability of Bacopa monnieri for long-term operations that lead to the practical application of phytoremediation in textile industries.

Comparing the performance of granular coral limestone and Leca in adsorbing Acid Cyanine 5R from aqueous solution

The effect of granular coral limestone and Leca as adsorbents for removing Acid Cyanine 5R (AC5R) from aqueous solution was studied. The optimum pH and adsorbent particles size in both adsorbents were determined to be 3 and 297 μm, respectively. The optimum dosages of coral limestone and granular Leca were 0.150 and 0.145 g/mg of dye, respectively. Also, results have shown that the adsorption efficiency by both coral limestone and Leca increased with the decreasing adsorbent particles size. Moreover, under similar conditions, the maximum removal efficiency by granular coral limestone and Leca was 94% and 88%, respectively. The results revealed that the performance of granular coral limestone was better in AC5R removal than that of Leca granulated under such condition. In total, granular coral limestone and Leca act as suitable adsorbents for removing dye pollutants from an aqueous solution.