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In order to mitigate the harmful effects of eutrophication in water bodies, the applications of lanthanum-modified materials for phosphate removal from wastewater have attracted much attention. Unlike conventional adsorbents, plant wastes usually have poor adsorption abilities and are difficult to be reused for desorption of phosphate due to their small pore sizes and ununiform loading of modified ions. In this paper, a composite adsorbent (LC-MM) was synthesized by hydrothermal treatment of waste traditional Chinese medical materials (MMs) with load of lanthanum carbonate and co-heating treatment with coal fly ash (CFA), which was applied to remove phosphate from water. The results showed that maximum adsorption capacity of LC-MM was 52 mg g−1, and the LC-MM showed appreciable adsorption capacity of phosphate for agricultural wastewater in the presence of complex interfering ions and for urban surface waters with low phosphate concentrations. Five adsorption-desorption cycles showed good reusability. The mechanism study showed that the La3+ ions were more uniformly distributed on the surface of the absorbents with the introduction of Fe3+, Al3+, Mg2+ and Ca2+ ions in CFA. The ligand exchange between phosphate and carbonate, the internal spherical complexation formed by lanthanum ion and phosphate, and surface chemical precipitation attachment are the main reasons why the adsorption capacity of LC-MM approached or even surpassed that of conventional lanthanum-modified adsorbents. In conclusions, this work proposed an effective method for the modification of plant materials. [Display omitted] • Reuse of two types of waste after treatment. • A method to improve the inefficiency of phosphate adsorption by plant materials. • The mechanism of modification is to influence the state of lanthanum on the surface of the carrier. • Effect of phosphate separated after adsorption on plant growth. [ABSTRACT FROM AUTHOR]

In order to mitigate the harmful effects of eutrophication in water bodies, the applications of lanthanum-modified materials for phosphate removal from wastewater have attracted much attention. Unlike conventional adsorbents, plant wastes usually have poor adsorption abilities and are difficult to be reused for desorption of phosphate due to their small pore sizes and ununiform loading of modified ions. In this paper, a composite adsorbent (LC-MM) was synthesized by hydrothermal treatment of waste traditional Chinese medical materials (MMs) with load of lanthanum carbonate and co-heating treatment with coal fly ash (CFA), which was applied to remove phosphate from water. The results showed that maximum adsorption capacity of LC-MM was 52 mg g−1, and the LC-MM showed appreciable adsorption capacity of phosphate for agricultural wastewater in the presence of complex interfering ions and for urban surface waters with low phosphate concentrations. Five adsorption-desorption cycles showed good reusability. The mechanism study showed that the La3+ ions were more uniformly distributed on the surface of the absorbents with the introduction of Fe3+, Al3+, Mg2+ and Ca2+ ions in CFA. The ligand exchange between phosphate and carbonate, the internal spherical complexation formed by lanthanum ion and phosphate, and surface chemical precipitation attachment are the main reasons why the adsorption capacity of LC-MM approached or even surpassed that of conventional lanthanum-modified adsorbents. In conclusions, this work proposed an effective method for the modification of plant materials. [Display omitted] • Reuse of two types of waste after treatment. • A method to improve the inefficiency of phosphate adsorption by plant materials. • The mechanism of modification is to influence the state of lanthanum on the surface of the carrier. • Effect of phosphate separated after adsorption on plant growth. [ABSTRACT FROM AUTHOR]

Reuse of agricultural and industrial wastes simultaneously to prepare hydrochars (HCs) for removal of NH 4 + and PO 4 3− in practical sewage without additional wastes produced is still a challenge. Herein, HCs were fabricated by combination of rape straw and industrial sewage sludge to remove NH 4 + and PO 4 3− from hoggery effluent. Synthesis conditions were firstly optimized and optimized HC (OPT-HC) was further applied to adsorb NH 4 + and PO 4 3−. Monolayer and Pseudo-first-order as well as Pseudo-second-orders were confirmed via adsorption kinetic and isothermal adsorption studies. Morphologies and surface areas of the OPT-HC did not show any transformations before and after adsorption of NH 4 + and PO 4 3−. The OPT-HC after adsorption of NH 4 + and PO 4 3− (OPT–HC–N/P) was further applied as fertilizer for planting Ping-pong Chrysanthemum. Results indicate that the OPT–HC–N/P can improve comprehensive qualities of the Ping-pong Chrysanthemum such as plant height, fresh, Vitamin C, Chlorophyll, soluble protein and sugar because the OPT–HC–N/P can provide extra N and P elements and also promote to release available K in soil. OPT–HC–N/P treated Ping-pong Chrysanthemum open flowers in advance. Thus, two kinds of wastes were re-utilized to remove N and P in real-life effluent. • Agricultural and industrial wastes were used to prepare hydrochars. • The hydrochars can be applied to remove N and P in hoggery effluent. • No wastes produced after removal of N and P. • Horticultural/agricultural applications were further realized. • Qualities of Ping-pong Chrysanthemum improved by HC after adsorption of N and P. [ABSTRACT FROM AUTHOR]