Source: http://revistapolimeros.org.br/doi/10.1590/0104-1428.09316
Timestamp: 2019-04-22 07:10:28+00:00

Document:
Polymers are a class of soft materials with numerous and versatile mechanical and chemical properties that can be tuned specific to their application. Agriculture is an expanding area due to the requirement for indispensable food to meet the demands of a growing global population. Consequently, development of technology to improve the quality of the soil and agriculture manages is still under development. Intelligent agricultural supplies (controlled or slow release agrochemicals and superabsorbents) and biosorbents contribute to an expanding niche using technology from polymers. This review elucidates the state-of-the-art and will discuss some important aspects of using polymers in intelligent fertilizers, as well as superabsorbent, biosorbent and biodegradation processes in agriculture that are environmentally, technically, socially, and economically sustainable.
controlled delivery system, biosorption, superabsorbent, biodegradation.
1. Food and Agriculture Organization of the United Nations. (2011). The state of the world’s land and water resources for food and agriculture (SOLAW) – managing systems at risk. Rome: FAO.
2. Tilman, D., Cassman, K. G., Matson, P. A., Naylor, R., & Polasky, S. (2002). Agricultural sustainability and intensive production practices. Nature, 418(6898), 671-677. PMid:12167873. http://dx.doi.org/10.1038/nature01014.
4. Puoci, F., Iemma, F., Spizzirri, U. G., Cirillo, G., Curcio, M., & Picci, N. (2008). Polymer in agriculture: a review. American Journal of Agricultural and Biological Sciences, 3(1), 299-314. http://dx.doi.org/10.3844/ajabssp.2008.299.314.
6. Roy, A., Singh, S. K., Bajpai, J., & Bajpai, A. K. (2014). Controlled pesticide release from biodegradable polymers. Central European Journal of Chemistry, 12(4), 453-469. http://dx.doi.org/10.2478/s11532-013-0405-2.
7. Woodhouse, J., & Johnson, M. S. (1991). Effect of superabsorbent polymers on survival and growth of crop seedlings. Agricultural Water Management, 20(1), 63-70. http://dx.doi.org/10.1016/0378-3774(91)90035-H.
8. Sharma, S., Dua, A., & Malik, A. (2014). Polyaspartic acid based superabsorbent polymers. European Polymer Journal, 59, 363-376. http://dx.doi.org/10.1016/j.eurpolymj.2014.07.043.
9. Reetz, H. F., Jr. (2016). Fertilizers and their efficient use. Paris: IFA.
10. Trenkel, M. E. (2010). Slow- and controlled-release and stabilized fertilizers: an option for enhancing nutrient use efficiency in agriculture. Paris: IFA.
11. Pereira, E. I., Giroto, A. S., Bortolin, A., Yamamoto, C. F., Marconcini, J. M., de Campos Bernardi, A. C., & Ribeiro, C. (2015). Perspectives in nanocomposites for the slow and controlledrelease of agrochemicals: fertilizers and pesticides. In M. Rai, C. Ribeiro, L. Mattoso, & N. Duran (Eds.), Nanotechnologies in food and agriculture (pp. 241-265). Minneapolis: Springer. http://dx.doi.org/10.1007/978-3-319-14024-7_11.
12. Shaviv, A. (2001). Advances in controlled-release fertilizers. Advances in Agronomy, 71, 1-49. http://dx.doi.org/10.1016/S0065-2113(01)71011-5.
13. Trenkel, M. E. (1997). Controlled-release and stabilized fertilizers in agriculture (Vol. 11). Paris: International Fertilizer Industry Association.
14. Noppakundilograt, S., Pheatcharat, N., & Kiatkamjornwong, S. (2015). Multilayer coated NPK compound fertilizer hydrogel with controlled nutrient release and water absorbency. Journal of Applied Polymer Science, 132(2) http://dx.doi.org/10.1002/app.41249.
15. Du, C. W., Zhou, J. M., & Shaviv, A. (2006). Release characteristics of nutrients from polymer-coated compound controlled-release fertilizers. Journal of Polymers and the Environment, 14(3), 223-230. http://dx.doi.org/10.1007/s10924-006-0025-4.
16. Melaj, M. A., & Daraio, M. E. (2013). Preparation and characterization of potassium nitrate controlled release fertilizers based on chitosan and xanthan layered tablets. Journal of Applied Polymer Science, 130(4), 2422-2428. http://dx.doi.org/10.1002/app.39452.
17. Oertli, J. J., & Lunt, O. R. (1962). Controlled-release of fertilizer minerals by incapsulating membranes: I. Factors influencing the rate of release. Soil Science Society of America Journal, 26(6), 579-583. http://dx.doi.org/10.2136/sssaj1962.03615995002600060019x.
18. Al-Zahrani, S. M. (1999). Controlled-release of fertilizers: modelling and simulation. International Journal of Engineering Science, 37(10), 1299-1307. http://dx.doi.org/10.1016/S0020-7225(98)00120-7.
19. Allan, G. G., Chopra, C. S., Neogi, A. N., & Wilkins, R. M. (1971). Design and synthesis of controlled-release pesticide-polymer combinations. Nature, 234(5328), 349-351. PMid:4944486. http://dx.doi.org/10.1038/234349a0.
20. Lvov, Y. M., Shchukin, D. G., Mohwald, H., & Price, R. R. (2008). Halloysite clay nanotubes for controlled-release of protective agents. ACS Nano, 2(5), 814-820. PMid:19206476. http://dx.doi.org/10.1021/nn800259q.
21. Qian, K., Shi, T., Tang, T., Zhang, S., Liu, X., & Cao, Y. (2011). Preparation and characterization of nano-sized calcium carbonate as controlled-release pesticide carrier for validamycin against Rhizoctonia solani. Mikrochimica Acta, 173(1-2), 51-57. http://dx.doi.org/10.1007/s00604-010-0523-x.
22. Pérez de Luque, A., & Hermosín, M. C. (2013). Nanotechnology and its use in agriculture. In D.Bagchi (Ed.), Bio-nanotechnology: a revolution in food, biomedical and health sciences (pp. 383-398). Oxford: Blackwell Publishing Ltd. http://dx.doi.org/10.1002/9781118451915.ch20.
23. Kashyap, P. L., Xiang, X., & Heiden, P. (2015). Chitosan nanoparticle based delivery systems for sustainable agriculture. International Journal of Biological Macromolecules, 77, 36-51. PMid:25748851. http://dx.doi.org/10.1016/j.ijbiomac.2015.02.039.
24. Ibrahim, S., Nawwar, G. A., & Sultan, M. (2016). Development of bio-based polymeric hydrogel: green, sustainable and low cost plant fertilizer packaging material. Journal of Environmental Chemical Engineering, 4(1), 203-210. http://dx.doi.org/10.1016/j.jece.2015.10.028.
25. Hussain, M. R., Devi, R. R., & Maji, T. K. (2012). Controlledrelease of urea chitosan microspheres prepared by emulsification and cross—linking method. Iranian Polymer Journal, 21(8), 473-479. http://dx.doi.org/10.1007/s13726-012-0051-0.
26. Costa, M. M. E., Cabral-Albuquerque, E. C. M., Alves, T. L., Pinto, M. J. C., & Fialho, R. L. (2013). Use of polyhydroxybutyrate and ethyl cellulose for coating of urea granules. Journal of Agricultural and Food Chemistry, 61(42), 9984-9991. PMid:24059839. http://dx.doi.org/10.1021/jf401185y.
27. Azeem, B., KuShaari, K., Man, Z. B., Basit, A., & Thanh, T. H. (2014). Review on materials & methods to produce controlledrelease coated urea fertilizer. Journal of Controlled Release, 181, 11-21. PMid:24593892. http://dx.doi.org/10.1016/j.jconrel.2014.02.020.
28. Sabadini, R. C., Martins, V. C., & Pawlicka, A. (2015). Synthesis and characterization of gellan gum: chitosan biohydrogels for soil humidity control and fertilizer release. Cellulose, 22(3), 2045-2054. http://dx.doi.org/10.1007/s10570-015-0590-6.
29. Noppakundilograt, S., Pheatcharat, N., & Kiatkamjornwong, S. (2015). Multilayer coated NPK compound fertilizer hydrogel with controlled nutrient release and water absorbency. Journal of Applied Polymer Science, 132(2) http://dx.doi.org/10.1002/app.41249.
30. Lubkowski, K., & Grzmil, B. (2007). Controlled-release fertilizers. Polish Journal of Chemical Technology, 9(4), 81-84. http://dx.doi.org/10.2478/v10026-007-0096-6.
31. Senna, A. M., Carmo, J. B., Silva, J. M. S., & Botaro, V. R. (2015). Synthesis, characterization and application of hydrogel derived from cellulose acetate as a substrate for slowrelease NPK fertilizer and water retention in soil. Journal of Environmental Chemical Engineering, 3(2), 996-1002. http://dx.doi.org/10.1016/j.jece.2015.03.008.
32. Ahmad, N. N. R., Fernando, W. J. N., & Uzir, M. H. (2015). Parametric evaluation using mechanistic model for release rate of phosphate ions from chitosan-coated phosphorus fertiliser pellets. Biosystems Engineering, 129, 78-86. http://dx.doi.org/10.1016/j.biosystemseng.2014.09.015.
33. Melaj, M. A., & Daraio, M. E. (2014). HPMC layered tablets modified with chitosan and xanthan as matrices for controlled‐ release fertilizers. Journal of Applied Polymer Science, 131(19), 40839. http://dx.doi.org/10.1002/app.40839.
34. Santos, B. R., Bacalhau, F. B., Pereira, T. S., Souza, C. F., & Faez, R. (2015). Chitosan-montmorillonite microspheres: a sustainable fertilizer delivery system. Carbohydrate Polymers, 127, 340-346. PMid:25965492. http://dx.doi.org/10.1016/j.carbpol.2015.03.064.
35. Messa, L. L., Froes, J. D., Souza, C. F., & Faez, R. (2016). Híbridos de quitosana-argila para encapsulamento e liberação sustentada do fertilizante nitrato de potássio. Quimica Nova, 39(10), 1215-1220. http://dx.doi.org/10.21577/0100-4042.20160133.
36. Grillo, R., Clemente, Z., Oliveira, J. L., Campos, E. V. R., Chalupe, V. C., Jonsson, C. M., Lima, R., Sanches, G., Nishisaka, C. S., Rosa, A. H., Oehlke, K., Greiner, R., & Fraceto, L. F. (2015). Chitosan nanoparticles loaded the herbicide paraquat: the influence of the aquatic humic substances on the colloidal stability and toxicity. Journal of Hazardous Materials, 286, 562-572. PMid:25636059. http://dx.doi.org/10.1016/j.jhazmat.2014.12.021.
37. Celis, R., Adelino, M. A., Hermosín, M. C., & Cornejo, J. (2012). Montmorillonite–chitosan bionanocomposites as adsorbents of the herbicide clopyralid in aqueous solution and soil/water suspensions. Journal of Hazardous Materials, 209-210, 67-76. PMid:22284171. http://dx.doi.org/10.1016/j.jhazmat.2011.12.074.
38. Liu, F., Wen, L. X., Li, Z. Z., Yu, W., Sun, H. Y., & Chen, J. F. (2006). Porous hollow silica nanoparticles as controlled delivery system for water-soluble pesticide. Materials Research Bulletin, 41(12), 2268-2275. http://dx.doi.org/10.1016/j.materresbull.2006.04.014.
39. Azeem, B., KuShaari, K., Man, Z. B., Basit, A., & Thanh, T. H. (2014). Review on materials & methods to produce controlledrelease coated urea fertilizer. Journal of Controlled Release, 181, 11-21. PMid:24593892. http://dx.doi.org/10.1016/j.jconrel.2014.02.020.
40. Davidson, D., & Gu, F. X. (2012). Materials for sustained and controlled-release of nutrients and molecules to support plant growth. Journal of Agricultural and Food Chemistry, 60(4), 870-876. PMid:22224363. http://dx.doi.org/10.1021/jf204092h.
41. Akiyama, H., Yan, X., & Yagi, K. (2010). Evaluation of effectiveness of enhanced efficiency fertilizers as mitigation options for N2O and NO emissions from agricultural soils: meta analysis. Global Change Biology, 16(6), 1837-1846. http://dx.doi.org/10.1111/j.1365-2486.2009.02031.x.
42. Dubey, S., Jhelum, V., & Patanjali, P. K. (2011). Controlledrelease agrochemicals formulations: a review. Journal of Scientific and Industrial Research, 70(2), 105-112.
43. Ghormade, V., Deshpande, M. V., & Paknikar, K. M. (2011). Perspectives for nano-biotechnology enabled protection and nutrition of plants. Biotechnology Advances, 29(6), 792-803. PMid:21729746. http://dx.doi.org/10.1016/j.biotechadv.2011.06.007.
44. Shavit, U., Shaviv, A., Shalit, G., & Zaslavsky, D. (1997). Release characteristics of a new controlled-release fertilizer. Journal of Controlled Release, 43(2), 131-138. http://dx.doi.org/10.1016/S0168-3659(96)01478-2.
45. Shavit, U., Reiss, M., & Shaviv, A. (2003). Wetting mechanisms of gel-based controlled-release fertilizers. Journal of Controlled Release, 88(1), 71-83. PMid:12586505. http://dx.doi.org/10.1016/S0168-3659(02)00455-8.
46. Lu, S. M., & Lee, S. F. (1992). Slow release of urea through latex film. Journal of Controlled Release, 18(2), 171-180. http://dx.doi.org/10.1016/0168-3659(92)90187-V.
47. Buwalda, S. J., Boere, K. W., Dijkstra, P. J., Feijen, J., Vermonden, T., & Hennink, W. E. (2014). Hydrogels in a historical perspective: From simple networks to smart materials. Journal of Controlled Release, 190, 254-273. PMid:24746623. http://dx.doi.org/10.1016/j.jconrel.2014.03.052.
48. Künzler, J. F. (1996). Silicone hydrogels for contact lens application. Trends in Polymer Science, 2(4), 52-59.
49. Nicolson, P. C., & Vogt, J. (2001). Soft contact lens polymers: an evolution. Biomaterials, 22(24), 3273-3283. PMid:11700799. http://dx.doi.org/10.1016/S0142-9612(01)00165-X.
50. Kopeček, J. (2009). Hydrogels: From soft contact lenses and implants to self assembled nanomaterials. Journal of Polymer Science. Part A, Polymer Chemistry, 47(22), 5929-5946. PMid:19918374. http://dx.doi.org/10.1002/pola.23607.
51. Kellenberger, S. R. (1992). US Patent No. 5.147.343. Washington: U.S. Patent and Trademark Office.
52. Kozak, T. F. (1975). US Patent No. 3.890.974. Washington: U.S. Patent and Trademark Office.
53. Peppas, N. A. (1997). Hydrogels and drug delivery. Current Opinion in Colloid & Interface Science, 2(5), 531-537. http://dx.doi.org/10.1016/S1359-0294(97)80103-3.
54. Peppas, N. A., Keys, K. B., Torres-Lugo, M., & Lowman, A. M. (1999). Poly (ethylene glycol)-containing hydrogels in drug delivery. Journal of Controlled Release, 62(1-2), 81-87. PMid:10518639. http://dx.doi.org/10.1016/S0168- 3659(99)00027-9.
55. Kamath, K. R., & Park, K. (1993). Biodegradable hydrogels in drug delivery. Advanced Drug Delivery Reviews, 11(1), to sim 59-84. http://dx.doi.org/10.1016/0169-409X(93)90027-2.
56. Zohuriaan-Mehr, M. J., Omidian, H., Doroudiani, S., & Kabiri, K. (2010). Advances in non-hygienic applications of superabsorbent hydrogel materials. Journal of Materials Science, 45(21), 5711-5735. http://dx.doi.org/10.1007/s10853-010-4780-1.
57. Erickson, R. E. (1984). US Patent No. 4.424.247. Washington: U.S. Patent and Trademark Office.
58. Redenbaugh, M. K. (1988). US Patent No. 4.779.376. Washington: U.S. Patent and Trademark Office.
59. Ullah, F., Othman, M. B., Javed, F., Ahmad, Z., & Md Akil, H. (2015). Classification, processing and application of hydrogels: a review. Materials Science and Engineering C, 57, 414-433. PMid:26354282. http://dx.doi.org/10.1016/j.msec.2015.07.053.
60. Zohuriaan-Mehr, M. J., Omidian, H., Doroudiani, S., & Kabiri, K. (2010). Advances in non-hygienic applications of superabsorbent hydrogel materials. Journal of Materials Science, 45(21), 5711-5735. http://dx.doi.org/10.1007/s10853-010-4780-1.
61. Samchenko, Y., Ulberg, Z., & Korotych, O. (2011). Multipurpose smart hydrogel systems. Advances in Colloid and Interface Science, 168(1-2), 247-262. PMid:21782148. http://dx.doi.org/10.1016/j.cis.2011.06.005.
62. Callaghan, T. V., Abdelnour, H., & Lindley, D. K. (1988). The environmental crisis in the Sudan: the effect of water-absorbing synthetic polymers on tree germination and early survival. Journal of Arid Environments, 14(3), 301-317.
63. Woodhouse, J., & Johnson, M. S. (1991). Effect of superabsorbent polymers on survival and growth of crop seedlings. Agricultural Water Management, 20(1), 63-70. http://dx.doi.org/10.1016/0378-3774(91)90035-H.
64. Stahl, J. D., Cameron, M. D., Haselbach, J., & Aust, S. D. (2000). Biodegradation of superabsorbent polymers in soil. Environmental Science and Pollution Research International, 7(2), 83-88. PMid:19009427. http://dx.doi.org/10.1065/espr199912.014.
65. Sutherland, G. R., Haselbach, J., & Aust, S. D. (1997). Biodegradation of crosslinked acrylic polymers by a whiterot fungus. Environmental Science and Pollution Research International, 4(1), 16-20. PMid:19002412. http://dx.doi.org/10.1007/BF02986258.
66. Islam, M. R., Xue, X., Mao, S., Ren, C., Eneji, A. E., & Hu, Y. (2011). Effects of water saving superabsorbent polymer on antioxidant enzyme activities and lipid peroxidation in oat (Avena sativa L.) under drought stress. Journal of the Science of Food and Agriculture, 91(4), 680-686. PMid:21302322. http://dx.doi.org/10.1002/jsfa.4234.
67. Sharma, S., Dua, A., & Malik, A. (2014). Polyaspartic acid based superabsorbent polymers. European Polymer Journal, 59, 363-376. http://dx.doi.org/10.1016/j.eurpolymj.2014.07.043.
68. Cannazza, G., Cataldo, A., De Benedetto, E., Demitri, C., Madaghiele, M., & Sannino, A. (2014). Experimental assessment of the use of a novel superabsorbent polymer (SAP) for the optimization of water consumption in agricultural irrigation process. Water, 6(7), 2056-2069. http://dx.doi.org/10.3390/w6072056.
69. Dragan, E. S. (2014). Design and applications of interpenetrating polymer network hydrogels. A review. Chemical Engineering Journal, 243, 572-590. http://dx.doi.org/10.1016/j.cej.2014.01.065.
70. Chauhan, G. S., & Mahajan, S. (2002). Use of novel hydrogels based on modified cellulose and methacrylamide for separation of metal ions from water systems. Journal of Applied Polymer Science, 86(3), 667-671. http://dx.doi.org/10.1002/app.10943.
71. Zhan, F., Liu, M., Guo, M., & Wu, L. (2004). Preparation of superabsorbent polymer with slow release phosphate fertilizer. Journal of Applied Polymer Science, 92(5), 3417-3421. http://dx.doi.org/10.1002/app.20361.
72. Liang, R., Liu, M., & Wu, L. (2007). Controlled-release NPK compound fertilizer with the function of water retention. Reactive & Functional Polymers, 67(9), 769-779. http://dx.doi.org/10.1016/j.reactfunctpolym.2006.12.007.
73. Jamnongkan, T., & Kaewpirom, S. (2010). Potassium release kinetics and water retention of controlled-release fertilizers based on chitosan hydrogels. Journal of Polymers and the Environment, 18(3), 413-421. http://dx.doi.org/10.1007/s10924-010-0228-6.
74. Wang, J., & Chen, C. (2009). Biosorbents for heavy metals removal and their future. Biotechnology Advances, 27(2), 195-226. PMid:19103274. http://dx.doi.org/10.1016/j.biotechadv.2008.11.002.
76. Gonçalves, A. C., Jr., Luchese, E. B., & Lenzi, E. (2000). Avaliação da fitodisponibilidade de cádmio, chumbo e crômio, em soja cultivada em Latossolo Vermelho escuro tratado com fertilizantes comerciais. Quimica Nova, 23(2), 173-177. http://dx.doi.org/10.1590/S0100-40422000000200006.
78. Zhiming, Z., Zhanbin, H., Ke, T., & Entong, L. (2013, August). The leaching research of environmental materials on Pb and Cd contaminated soil. In Proceedings of the 2013 the International Conference on Remote Sensing, Environment and Transportation Engineering (RSETE 2013) (pp. 493- 496). Nanjing, China: Atlantis Press.
79. Steffen, G. P. K., Steffen, R. B., & Antoniolli, Z. I. (2011). Contaminação do solo e da água pelo uso de agrotóxicos. Tecnologica, 15(1), 15-21. http://dx.doi.org/10.17058/tecnolog. v15i1.2016.
80. Rangabhashiyam, S., Anu, N., Giri Nandagopal, M. S., & Selvaraju, N. (2014). Relevance of isotherm models in biosorption of pollutants by agricultural byproducts. Journal of Environmental Chemical Engineering, 2(1), 398-414. http://dx.doi.org/10.1016/j.jece.2014.01.014.
81. Airoldi, C. (2008). A relevante potencialidade dos centros básicos nitrogenados disponíveis em polímeros inorgânicos e biopolímeros na remoção catiônica. Quimica Nova, 31(1), 144-153. http://dx.doi.org/10.1590/S0100-40422008000100026.
82. Demirbas, A. (2008). Heavy metal adsorption onto agro-based waste materials: a review. Journal of Hazardous Materials, 157(2-3), 220-229. PMid:18291580. http://dx.doi.org/10.1016/j.jhazmat.2008.01.024.
83. Wan Ngah, W. S., Teong, L. C., & Hanafiah, M. A. K. M. (2011). Adsorption of dyes and heavy metal ions by chitosan composites: a review. Carbohydrate Polymers, 83(4), 1446- 1456. http://dx.doi.org/10.1016/j.carbpol.2010.11.004.
84. Davis, T. A., Volesky, B., & Mucci, A. (2003). A review of the biochemistry of heavy metal biosorption by brown algae. Water Research, 37(18), 4311-4330. http://dx.doi.org/10.1016/S0043-1354(03)00293-8.
86. Kavamura, V. N., & Esposito, E. (2010). Biotechnological strategies applied to the decontamination of soils polluted with heavy metals. Biotechnology Advances, 28(1), 61-69. PMid:19778598. http://dx.doi.org/10.1016/j.biotechadv.2009.09.002.
87. Pal, A., & Paul, A. K. (2008). Microbial extracellular polymeric substances: central elements in heavy metal bioremediation. Indian Journal of Microbiology, 48(1), 49-64. PMid:23100700. http://dx.doi.org/10.1007/s12088-008-0006-5.
88. Ferreira, P. P. L., Braga, R. M., Teodoro, N. M. A., Melo, V. R. M., Melo, D. M. A., & Melo, M. A. F. (2015). Adsorção de Cu 2+ e Cr 3+ em efluentes líquidos utilizando a cinza do bagaço da cana-de-açúcar. Cerâmica, 61(360), 435-441. http://dx.doi.org/10.1590/0366-69132015613601945.
89. Zolgharnein, J., Asanjarani, N., & Shariatmanesh, T. (2011). Removal of thallium(I) from aqueous solution using modified sugar beet pulp. Toxicological and Environmental Chemistry, 93(2), 207-214. http://dx.doi.org/10.1080/02772248.2010.52 3424.
90. Kumar, S., & Meikap, B. C. (2014). Removal of chromium (VI) from waste water by using adsorbent prepared from green coconut shell. Desalination and Water Treatment, 52(16-18), 3122-3132. http://dx.doi.org/10.1080/19443994.2013.80179 6.
91. Tao, Y., Ye, L., Pan, J., Wang, Y., & Tang, B. (2009). Removal of Pb (II) from aqueous solution on chitosan/TiO 2 hybrid film. Journal of Hazardous Materials, 161(2-3), 718-722. PMid:18495341. http://dx.doi.org/10.1016/j.jhazmat.2008.04.012.
93. Dal Magro, C., Deon, M. C., Thomé, A., Piccin, J. S., & Colla, L. M. (2013). Biossorção passiva de cromo (VI) através da microalga Spirulina platensis. Quimica Nova, 36(8), 1139-1145. http://dx.doi.org/10.1590/S0100-40422013000800011.
94. Sobhanardakani, S., Parvizimosaed, H., & Olyaie, E. (2013). Heavy metals removal from wastewaters using organic solid waste—rice husk. Environmental Science and Pollution Research International, 20(8), 5265-5271. PMid:23381799. http://dx.doi.org/10.1007/s11356-013-1516-1.
95. Anwar, J., Shafique, U., Waheed-uz-Zaman, Salman, M., Dar, A., & Anwar, S. (2010). Removal of Pb (II) and Cd (II) from water by adsorption on peels of banana. Bioresource Technology, 101(6), 1752-1755. PMid:19906528. http://dx.doi.org/10.1016/j.biortech.2009.10.021.
96. Paulino, Á. G., Cunha, A. J., Alfaya, R. V. S., & Alfaya, A. A. S. (2014). Chemically modified natural cotton fiber: a low-cost biosorbent for the removal of the Cu(II), Zn(II), Cd(II), and Pb(II) from natural water. Desalination and Water Treatment, 52(22-24), 4223-4233. http://dx.doi.org/10.1080/19443994.2 013.804451.
97. Barka, N., Abdennouri, M., Boussaoud, A., & EL Makhfouk, M. (2010). Biosorption characteristics of Cadmium (II) onto Scolymus hispanicus L. as low-cost natural biosorbent. Desalination, 258(1), 66-71. http://dx.doi.org/10.1016/j.desal.2010.03.046.
98. Mahmoud, M. E., Yakout, A. A., Abdel-Aal, H., & Osman, M. M. (2013). Immobilization of Fusarium verticillioides fungus on nano-silica (NSi–Fus): A novel and efficient biosorbent for water treatment and solid phase extraction of Mg (II) and Ca (II). Bioresource Technology, 134, 324-330. PMid:23517902. http://dx.doi.org/10.1016/j.biortech.2013.01.171.
99. Lucas, N., Bienaime, C., Belloy, C., Queneudec, M., Silvestre, F., & Nava-Saucedo, J. E. (2008). Polymer biodegradation: mechanisms and estimation techniques. Chemosphere, 73(4), 429-442. PMid:18723204. http://dx.doi.org/10.1016/j.chemosphere.2008.06.064.
100. Watanabe, T., Ohtake, Y., Asabe, H., Murakami, N., & Furukawa, M. (2009). Biodegradability and degrading microbes of low density polyethylene. Journal of Applied Polymer Science, 111(1), 551-559. http://dx.doi.org/10.1002/app.29102.
101. Ge, J., Wu, R., Shi, X., Yu, H., Wang, M, & Li, W. (2002). Biodegradable polyurethane materials from bark and starch. II. Coating material for controlled release fertilizer. Journal of Applied Polymer Science, 86(12), 2948-2952. http://dx.doi.org/10.1002/app.11211.
102. Shah, A. A., Hasan, F., Hameed, A., & Ahmed, S. (2008). Biological degradation of plastics: a comprehensive review. Biotechnology Advances, 26(3), 246-265. PMid:18337047. http://dx.doi.org/10.1016/j.biotechadv.2007.12.005.
103. Roseman, T. J. (1972). Release of steroids from a silicone polymer. Journal of Pharmaceutical Sciences, 61(1), 46-50. PMid:5058644. http://dx.doi.org/10.1002/jps.2600610106.
104. Ritger, P. L., & Peppas, N. A. (1987). A simple equation for description of solute release I. Fickian and non-Fickian release from non-swellable devices in the form of slabs, spheres, cylinders or discs. Journal of Controlled Release, 5(1), 23-36. http://dx.doi.org/10.1016/0168-3659(87)90034-4.
105. Saruchi, K., Kaith, B. S., Jindal, R., & Kumar, V. (2015). Biodegradation of Gum tragacanth acrylic acid based hydrogel and its impact on soil fertility. Polymer Degradation & Stability, 115, 24-31. http://dx.doi.org/10.1016/j.polymdegradstab.2015.02.009.
106. Ye, H., Zhao, J. Q. & Zhang, Y. H., (2004). Novel degradable superabsorbent materials of silicate/acrylic based polymer hybrids. Journal of Applied Polymer Science, 91(2), 936-940. http://dx.doi.org/10.1002/app.13274.
107. Wilske, B., Bai, M., Lindenstruth, B., Bach, M., Rezaie, Z., Frede, H. G., & Breuer, L. (2014). Biodegradability of a polyacrylate superabsorbent in agricultural soil. Environmental Science and Pollution Research International, 21(16), 9453-9460. PMid:24037296. http://dx.doi.org/10.1007/s11356-013-2103-1.

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